Color FISH Research Articles

Effect of Spirulina Flour Addition in Feed on the Increase of Colour Brightness Nemo Fish (Premnas biaculeatus)

The nemo fish (Premnas biaculeatus) is a type of marine ornamental fish in Indonesia that is in high demand among the general public. The popularity of this fish can be attributed to several factors, one of which is the brightness of its coloration. One of the plants that can be employed as a color enhancer for ornamental fish is spirulina. Spirulina is a microalgae that has been demonstrated to enhance the brightness of fish coloration. Therefore, it is necessary to research on the effect of adding spirulina flour to feed on increasing the brightness of the color of nemo fish (Premnas biaculeatus). The method used in this research is an experimental method with a completely randomized design. This treatment was carried out with 5 treatments and 3 repetitions, namely: P0 : 0%/kg, P1 : 2%/kg, P2 : 4%/kg, P3 : 6%/kg and P4 : 8%/kg. The 5 treatments were repeated 3 times, resulting in 15 experimental units. The results of the researches carried out, it can be concluded that the addition of spirulina flour to feed on the brightness of the color of nemo fish (Premnas biaculeatus) is proven to increase the brightness of the color of nemo fish and the best treatment is p3 with a dose of 6%. The addition of spirulina flour to feed on the growth of length and absolute weight of nemo fish (Premnas biaculeatus) has a significant effect, while the survival rate has no significant effect.

How life became colourful: colour vision, aposematism, sexual selection, flowers, and fruits.

Plants and animals are often adorned with potentially conspicuous colours (e.g. red, yellow, orange, blue, purple). These include the dazzling colours of fruits and flowers, the brilliant warning colours of frogs, snakes, and invertebrates, and the spectacular sexually selected colours of insects, fish, birds, and lizards. Such signals are often thought to utilize pre-existing sensitivities in the receiver's visual systems. This raises the question: what was the initial function of conspicuous colouration and colour vision? Here, we review the origins of colour vision, fruit, flowers, and aposematic and sexually selected colouration. We find that aposematic colouration is widely distributed across animals but relatively young, evolving only in the last ~150 million years (Myr). Sexually selected colouration in animals appears confined to arthropods and chordates, and is also relatively young (generally <100 Myr). Colourful flowers likely evolved ~200 million years ago (Mya), whereas colourful fruits/seeds likely evolved ~300 Mya. Colour vision (sensu lato) appears to be substantially older, and likely originated ~400-500 Mya in both arthropods and chordates. Thus, colour vision may have evolved long before extant lineages with fruit, flowers, aposematism, and sexual colour signals. We also find that there appears to have been an explosion of colour within the last ~100 Myr, including >200 origins of aposematic colouration across nine animal phyla and >100 origins of sexually selected colouration among arthropods and chordates.

Specific gut microbiome's role in skin pigmentation: insights from SCARB1 mutants in Oujiang colour common carp.

Beyond the pivotal roles of the gut microbiome in initiating physiological processes and modulating genetic factors, a query persists: Can a single gene mutation alter the abundance of the gut microbiome community? Not only this, but the intricate impact of gut microbiome composition on skin pigmentation has been largely unexplored. Based on these premises, our study examines the abundance of lipase-producing gut microbes about differential gene expression associated with bile acid synthesis and lipid metabolism-related blood metabolites in red (whole wild) and white (whole white wild and SCARB1-/- mutant) Oujiang colour common carp. Following the disruption of the SCARB1 gene in the resulting mutant fish with white body colour (SCARB1-/-), there is a notable decrease in the abundance of gut microbiomes (Bacillus, Staphylococcus, Pseudomonas, and Serratia) associated with lipase production. This reduction parallels the downregulation seen in wild-type white body colour fish (WW), as contrasting to the wild-type red body colour fish (WR). Meanwhile, in SCARB1-/- fish, there was a downregulation noted not only at the genetic and metabolic levels but also a decrease in lipase-producing bacteria. This consistency with WW contrasts significantly with WR. Similarly, genes involved in the bile acid synthesis pathway, along with blood metabolites related to lipid metabolism, exhibited downregulation in SCARB1-/- fish. The SCARB1 knockout gene blockage led to significant alterations in the gut microbiome, potentially influencing the observed reduction in carotenoid-associated skin pigmentation. Our study emphasizes that skin pigmentation is not only impacted by genetic factors but also by the gut microbiome. Meanwhile, the gut microbiome's adaptability can be rapidly shaped and may be driven by specific single-gene variations.

Effects of Different Roasting Methods on the Quality of Roasted Large Yellow Croaker (Larimichthys crocea).

This study investigated the effects of different roasting methods (45% light wave and 55% microwave roasting, 70% light wave and 30% microwave roasting, 100% light wave roasting, far-infrared roasting, and oven roasting) on the quality of roasted large yellow croaker. The quality was evaluated using sensory evaluation, texture characteristics, color differences, moisture content, and volatile flavor substances. In this context, different roasting methods can affect the color, taste, and flavor of large yellow croaker fish, significantly improving the overall acceptance of roasted fish. The results showed that after 45% light wave and 55% microwave roasting, the elasticity of fish meat was maintained, the hardness of fish meat was reduced, the moisture content and distribution were changed, and the taste was the best. Far-infrared roasting and 45% light wave and 55% microwave roasting had a significant effect on the color of large yellow croaker samples and improved the sensory evaluation score. Forty-six volatile compounds were detected using gas chromatography-mass spectrometry. After roasting, the oxidation and Maillard reactions of lipids and proteins were increased, with the 45% light wave and 55% microwave roasting giving the highest variety of volatile flavor substance products.

Growth and Color Brightness of Glofish Fed Natural and Artificial Diets In Cianjur District, West Java Province

It is known that natural feed, in addition to being preferred because it moves, also has dyes that make the color of ornamental fish more contrasting than artificial feed. The purpose of this study is to find out which type of natural feed (Silk Worm (Tubifex sp.), Daphnia sp., Frozen Blood Worm) and artificial feed, which is more effective against the growth and brightness of the color of Glofish Starfire Red, which will be carried out in August 2024-October 2024 in Cianjur Regency, West Java Province. The study was conducted using an experimental method using a Complete Random Design (RAL) with 4 treatments and 3 replicates. The treatment given is as follows: A (Research using natural feed Daphnia sp, B (Research using natural feed Bloodwarm/Chironomidae, C (Research using natural feed Tubifex sp), D (Research using artificial feed). The parameters observed were Absolute Length Growth, Absolute Weight Growth, Specific Growth Rate and Color Brightness, to analyze the color brightness of Starfire Red fish using https://redketchup.io color comparison.

Utilization of Indigofera zollingeriana leaves meal in feed formulation to color brightness and growth in koi fish (Cyprinus carpio)

This study aims to determine the effect of the addition of Indigofera zollingeriana in feed formulations with different doses on the color brightness of koi fish. The research design was Completely Randomized Design (CRD) with five treatments and three replications. Treatment P0 was control (without the use of Indigofera leaf meal), P1 was the addition of 5% indigofera meal, P2 was the addition of 10% indigofera meal, P3 was the addition of 15% indigofera meal, and P4 was the addition of 20% indigofera meal. Fingerlings measuring 6 ± 1 cm with a stocking density of 1 fish for 2 L were reared for 30 days in this study. The results showed that P2 with a percentage of 10% Indigofera zollingeriana meal was the best treatment for the brightness of koi fish color (27.23). Still, they had no significant effect on the growth of absolute length (1.04 cm) and absolute weight (1.05 g), feed efficiency (23.08%), and survival rate (100%). The water quality obtained during maintenance was temperature 26-27oC, pH 6.1-7.2, dissolved oxygen 5.2-6.3 mg/L, and ammonia 0.02-0.036 mg/L.Keywords: Fish Color Brightness; Indigofera zollingeriana; Koi Fish

Sexual selection may support phenotypic plasticity in male coloration of an African cichlid fish.

The expression of sexually selected traits, such as ornaments or body coloration, is often influenced by environmental conditions. While such phenotypic plasticity is often thought to precede evolutionary change, plasticity itself can also be a target of selection. However, the selective forces supporting the evolution and persistence of plasticity in sexual traits are often unclear. Using the cichlid fish Astatotilapia burtoni, we show that variation in the level of mate competition may promote plasticity in body coloration. In this species, males can change between yellow and blue colour. We found that experimentally increased competition over mating territories led to a higher proportion of males expressing the yellow phenotype. The expression of yellow coloration was found to be beneficial because yellow males won more staged dyadic contests and exhibited a lower level of oxidative stress than blue males. However, females were more likely to spawn with blue males in mate choice experiments, suggesting that expression of blue coloration is sexually more attractive. The ability to adjust colour phenotype according to the local competitive environment could therefore promote the persistence of plasticity in coloration.

The Effect Of Adding Natural Ingredients To Artificial Feeding On The Level Of Color Brightness Of Carp (Cyprinus carpio Linn)

The Effect of Adding Natural Ingredients to Artificial Feed on the Color Brightness Level of Goldfish (Cyprinus carpio Linn). This research aims to determine the effect of adding natural ingredients to artificial feed on the level of color brightness of goldfish (Cyprinus carpio Linn), and the growth rate and survival rate of the test fish. The method used in this research is an experimental method using a Completely Randomized Design (CRD) consisting of 4 treatments and 3 replications with a feeding frequency of three times per day with a percentage of 5% of the body weight of the test fish, a natural ingredient used in making artificial feed. These are pumpkin flour (Cucurbita moschata), mangosteen rind flour (Garcinia mangostana L), and carrot flour (Daucus carota L) with the same dose in each treatment, namely 25% of 1 kg of feed. Based on the results of variance analysis, the brightness level of goldfish color has a very real influence. The highest increase in the color of the test fish was obtained in treatment A, pumpkin flour, amounting to (1.37) on the Toca color finder scale (from pale orange to dark orange), followed by the second highest in treatment C, carrot flour, amounting to (1.2), treatment B flour. Mangosteen peel was in third position with an increase in color of (0.94) and the lowest increase in color change occurred in treatment D (control = without the addition of natural ingredients) of 0.7. However, absolute weight and length growth did not have a real influence. The overall graduation rate is 87.49%. The average water quality parameters are temperature 26-29oC, pH 7.5-7.9 and ammonia 0.25 ppm.

Do body colour and sociability impact scototaxis response of fish?

Scototaxis test is an anxiety-like test used by behavioural neuroscientists consisting in the assessment of dark/light preference of laboratory animals. This test has been widely used in fish. Most of the species have been shown to express a preference for the dark environment. However, the majority of the investigated species has a dark body colour, thus making a clear contrast with a white/bright background. Also, while in nature fish tend to be highly social, studies in the scototaxis literature tested single fish. Yet, individual vs. group behaviour might interact with scototaxis response. In experiment 1, we assessed the individual response to test the hypothesis that the different colours of the body might modulate the dark/light preference. We found that species with a dark body colour (Hyphessobrycon megalopterus) and a largely transparent body colour (Kryptopterus bicirrhis) strongly preferred the darker environment. Instead, the preference for darkness of a species with a luminescent part of the body (Paracheirodon axelrodi) was less pronounced. Lastly, a species with a white body colour (Corydoras albini) did not prefer either a bright or a dark sector. In experiment 2, we explored the behaviour of these species when inserted in shoals of 20 individuals in the experimental apparatus. While H. megalopterus and K. bichirrhis confirmed their robust preference for darker environments, the other two species changed their preference. Taken together, these results suggest that scototaxis response is context-dependent, as it appears to be modulated by the body colour and the presence/absence of other conspecifics in the surrounding.

Effect of Additional Dried Tubifex sp. in Commercial Feed Against Color Intensity of Guppy (Poecilia reticulata)

Guppy fish (Poecilia reticulata) is a type of ornamental fish that is in great demand, because of its small size and beautiful color. The color of ornamental fish will generally fade, due to a lack of carotenoids in their feed. The purpose of this study was to determine the effect of giving Tubifex sp. in commercial feed to increase the color intensity of guppy fish and the best dose of Tubifex sp. The test fish used were male guppy fish strain HB Red. This study used a completely randomized design (CRD) method with five treatments and three replications, that is commercial feed with the addition of Tubifex sp. with doses of 0% (P1), 2% (P2), 4% (P3), 6% (P4), and 8% (P5). Parameters observed were color intensity (chroma value), survival, and water quality. Addition of Tubifex sp. in commercial feed gave the effect with the highest yield on P5 at a dose of 8%, with an increase in color intensity (chroma value) of 4,21±0,25d. At P1 it gave an increase of 1,19±0,02a, P2 was 1,34±0,04a, P3 was 1,81±0,21b, and P4 was 2,88±0,18c. So, the best treatment is P5 (8%). Survival showed the results were not significantly different, that is 100%. Water quality is included in the tolerance limit of fish with the results of temperature 26,6 – 27,4°C, pH 7,4 – 7,9, and DO 6,2 – 7,7 mg/L.

Harnessing Hue: Advances and Applications of Fish Skin Pigmentation Genetics in Aquaculture

Fish exhibit a broad spectrum of colors and patterns facilitated by specialized cells known as chromatophores. The vibrant coloration of fish, controlled by complex genetic and environmental interactions, serves critical roles in ecological functions such as mating, predation, and camouflage. This diversity not only makes fish an invaluable model for exploring the molecular mechanisms of pigmentation but also significantly impacts their economic value within the aquaculture industry, where color traits can drive marketability and breeding choices. This review delves into the sophisticated biological processes governing fish pigmentation and discusses their applications in enhancing aquaculture practices. By exploring the intersection of genetic regulation, environmental influences, and advanced breeding techniques, this review highlights both the scientific understanding and practical applications of fish coloration, providing a bridge between basic biological research and its application in commercial aquaculture.

Compatibilities of Cyprinus carpio with Varied Colors of Robotic Fish

Visual selection plays a fundamental role in various aspects of animal behavior, such as colony formation, maintenance, defense, and courtship. This study investigated the effect of bionic robot fish color on carp behavior based on physiological characteristics that were observed during behavioral experiments. Through computer image processing and analysis of light attenuation, we observed changes in the number and positioning of carp with bionic robotic fish of different colors (white, red, blue, green, and yellow). The results indicated that (1) the attenuation coefficient of visible light in freshwater was red &gt; yellow &gt; green &gt; blue; (2) the order of the average change in the number of carp responding to different colors of robotic fish was white &gt; red &gt; green &gt; yellow &gt; blue, and carp were more sensitive and responsive to white and red robotic fish; and (3) the order of the distances between different colors of robotic fish and carp was white &lt; yellow &lt; blue &lt; green &lt; red, and white and yellow robotic fish were more attractive to carp. Therefore, the use of white or yellow robotic fish for relevant operations can reduce disturbance to fish schools.

Genome-wide association study reveals candidate genes critical for skin pigmentation in common carp (Cyprinus carpio) strains including koi

The differentiation and variation of body color in fish is an important component of biological evolution and phylogenetic research, and is influenced by several factors such as heredity, nutrition, physiological hormones and rearing conditions, with heredity being the most critical factor. An improved comprehension of the genetic regulation in different carp populations will facilitate future applications of precision breeding and pigment cell development-related genes editing. In this study, we used restriction site-associated DNA sequencing (2d-RAD) to determine the distribution characteristics of single nucleotide polymorphisms (SNPs) in eight common carp strains including six koi strains, i.e., Kohaku (Hb), Taisho (Dz), Showa (Zh), Golden (Hj), Matsukawabake (Sch) and Five-color (Ws), and two genetically improved breeding strains, i.e., FFRC No. 2 strain (Fr) and red FFRC strain (Hfr), and then SNP markers to resolve genetic information on the population structure and skin color formation of these strains. We found that most individuals of eight strains were clearly divided into eight clades. Genetic diversity within Fr, Sch and Ws is relatively high, while it is low within Dz, Hb and Hfr. A comparison between the populations revealed that Hfr and Ws have the highest degree of genetic differences, while Hb and Dz have the lowest. The GWAS analysis for two strategies identified several SNPs that are significantly related to skin color variation and affect melanin synthesis (ephrinb2, slc22a23, herc2, ephb2), carotenoid metabolism (oca2, bcmo1, bco2) and circadian rhythm(cipc). To summarize, our study provides some information on the genetic structure and diversity of Japanese koi and Chinese FFRC carp. Furthermore, based on the data obtained on relevant genes related to skin color differentiation and pigmentation, it can provide a theoretical basis for the subsequent integration of dominant traits and precision breeding in carps.

Effect of mushroom powder (Pleurotus ostreatus and Pleurotus djamor) on skin coloration and inflammation in siamese fighting fish (Betta splendens)

ABSTRACT Skin coloration and immune status are the most valued characteristics when raising Betta splendens. We evaluated the effects of enriching a cladoceran diet with Pleurotus ostreatus or P. djamor mushroom powder on coloration, response to induced injury, and growth of B. splendens. Seventeen fish per treatment (weight 0.60 ± 0.2 g) were assigned to three diets: Cladoceran powder (CP), CP enriched with P. ostreatus mushroom powder (CP + PO), and CP enriched with P. djamor mushroom powder (CP + PD). We evaluated color intensity, responses to induced injury, growth and condition factor (K) with each diet. We found that skin coloration and response to induced injury were improved with mushroom-supplemented diets. Body length and weight were higher with CP, while K was higher with CP and CP + PD diets (K = 3.29 and 2.66, respectively) than with CP + PO (K = 1.82). Our results contribute insights into the benefits of mushroom-supplemented diets for enhancing aquaculture.

A new insight into the pigmentation of the three-spined stickleback exposed to oxidative stress: day and night study

The diverse and changing pigmentation of the skin allows fish to adapt to environmental conditions for survival and communication with conspecifics. However, various physical and chemical environmental factors, including pollutants, affect fish coloration. Therefore, the implementation of an analysis of skin pigmentation has been considered in fish well-being and ecotoxicological studies. A physiological color change is achieved by the motility of melanin-containing organelles: they aggregate into the perikaryon or disperse throughout the cytoplasm of melanophores in response to various stimuli. In our study, we addressed the issue of implementing the analysis of pigment dispersion in melanophores in stickleback skin to assess the response of fish to oxidative stress. We examined pigment dispersion in day and night skin samples collected from the dorsal, lateral and ventral regions. The degree of pigment dispersion we assessed by the melanophore index. The total number of melanophores counted in the defined skin area was significantly higher in the night samples than in the day samples. Only in day samples of dorsal skin we observed the significant changes in pigment dispersion after exposure to stress: melanin was predominantly in the aggregated state. In the night samples, we did not report any response to stress in any part of the skin. Examination of pigment dispersion in melanophores in stickleback skin can be useful for assessing the welfare of fish and detecting toxic agents in the environment, but under specified conditions: in sticklebacks, it is analysis of dorsal skin during the day.

Pengaruh Pemberian Cacing Darah (Chironomus sp.) Kering Terhadap Kecerahan Warna Ikan Guppy (Peocilia reticulata)

This research aims to analyze the effect of adding natural blood worms (Chironomus sp) to the feed on the color of guppy fish (P. reticulate). The research was carried out for 50 days, at the Fish Production and Reproduction Laboratory, Mataram University using experimental methods with a completely randomized design (RAL ) consisting of 4 treatments and 3 repetitions, namely: A: Control feed (100%) B: 75% control feed and 25% dried blood worms C: 50% control feed and 50% dried blood worms and D: Control feed 25% and 75% dried blood worms. Test parameters include carotenoid content, brightness of fish color, absolute weight, specific growth rate, survival and water quality. Data were analyzed using Analysis of Variance (ANOVA) and continued with the Duncan test. The results of the research show that dried blood worms have the potential to be a source of natural carotenoids in increasing color brightness and do not have a negative impact on the growth and survival of guppy fish. The addition of up to 50% dried blood worms to the formulated feed was able to increase the color brightness of guppy fish with a Lightness (L*) value of 56.95, Redness (a*) of -0.09, Yellowness (b*) of 14.84 , Hue is 258.01 and Chroma value is 110.12

Morphological characteristics of sex dimorphism in Gobiopterus sp. (Gobiiformes: Oxudercidae) from Ranu Grati Lake, Pasuruan District, East Java, Indonesia

Abstract. Anitasari S, Arfiati D, Susilo, Marhendra APW. 2024. Morphological characteristics of sex dimorphism in Gobiopterus sp. (Gobiiformes: Oxudercidae) from Ranu Grati Lake, Pasuruan District, East Java, Indonesia. Biodiversitas 25: 1214-1222. Ranu Grati is a volcanic lake located in Pasuruan, East Java, Indonesia which has high ecological value as a habitat for a unique endemic fish found only in this lake, namely the Lempuk fish (Gobiopterus sp.). The aim of this research is to determine the morphological characters based on sexual dimorphism of Lempuk fish. in Ranu Grati Lake. The result showed the body color of male and female Lempuk fish is transparent. Lempuk fish do not have sexual dichromatism or their sex cannot be distinguished based on their body color. Lempuk fish have vomer teeth and canine teeth. Types of male and female ctenoid scales have a comb-like shape. The position of the mouth of the Lempuk Fish is located near the top or head of the fish but not precisely at the tip. There are variations in the superior subterminal mouth type between male and female fish, especially in terms of anatomical details and mouth structure. Based on meristic observations of the Lempuk fish, it can be explained that this fish has a fusiform body shape, this shows that gobies generally have a small fusiform body and also has pectoral fins, pelvic fins, dorsal fins, tail fins and anal fins. In this study, we found from histological observations of the Lempuk fish, mature oocytes and spermatids were found in one histological tissue sample at male fish with gonad maturity level II. This change from female to male occurs at the size of the fish with fish size of 21.21-30.58 ± 2.14mm. It indicates that is Lempuk fish is a species hermaphrodite protogyn.

Short-wavelength-sensitive 1 (SWS1) opsin gene duplications and parallel visual pigment tuning support ultraviolet communication in damselfishes (Pomacentridae).

Damselfishes (Pomacentridae) are one of the most behaviourally diverse, colourful and species-rich reef fish families. One remarkable characteristic of damselfishes is their communication in ultraviolet (UV) light. Not only are they sensitive to UV, they are also prone to have UV-reflective colours and patterns enabling social signalling. Using more than 50 species, we aimed to uncover the evolutionary history of UV colour and UV vision in damselfishes. All damselfishes had UV-transmitting lenses, expressed the UV-sensitive SWS1 opsin gene, and most displayed UV-reflective patterns and colours. We find evidence for several tuning events across the radiation, and while SWS1 gene duplications are generally very rare among teleosts, our phylogenetic reconstructions uncovered two independent duplication events: one close to the base of the most species-rich clade in the subfamily Pomacentrinae, and one in a single Chromis species. Using amino acid comparisons, we found that known spectral tuning sites were altered several times in parallel across the damselfish radiation (through sequence change and duplication followed by sequence change), causing repeated shifts in peak spectral absorbance of around 10 nm. Pomacentrinae damselfishes expressed either one or both copies of SWS1, likely to further finetune UV-signal detection and differentiation. This highly advanced and modified UV vision among damselfishes, in particular the duplication of SWS1 among Pomacentrinae, might be seen as a key evolutionary innovation that facilitated the evolution of the exuberant variety of UV-reflectance traits and the diversification of this coral reef fish lineage.

The interplay of local adaptation and gene flow may lead to the formation of supergenes.

Supergenes are genetic architectures resulting in the segregation of alternative combinations of alleles underlying complex phenotypes. The co-segregation of alleles at linked loci is often facilitated by polymorphic chromosomal rearrangements suppressing recombination locally. Supergenes are involved in many complex polymorphisms, including sexual, colour or behavioural polymorphisms in numerous plants, fungi, mammals, fish, and insects. Despite a long history of empirical and theoretical research, the formation of supergenes remains poorly understood. Here, using a two-island population genetic model, we explore how gene flow and the evolution of overdominant chromosomal inversions may jointly lead to the formation of supergenes. We show that the evolution of inversions in differentiated populations, both under disruptive selection, leads to an increase in frequency of poorly adapted, immigrant haplotypes. Indeed, rare allelic combinations, such as immigrant haplotypes, are more frequently reshuffled by recombination than common allelic combinations, and therefore benefit from the recombination suppression generated by inversions. When an inversion capturing a locally adapted haplotype spreads but is associated with a fitness cost hampering its fixation (e.g. a recessive mutation load), the maintenance of a non-inverted haplotype in the population is enhanced; under certain conditions, the immigrant haplotype persists alongside the inverted local haplotype, while the standard local haplotype disappears. This establishes a stable, local polymorphism with two non-recombining haplotypes encoding alternative adaptive strategies, that is, a supergene. These results bring new light to the importance of local adaptation, overdominance, and gene flow in the formation of supergenes and inversion polymorphisms in general.

The dwarf neon rainbowfish Melanotaenia praecox, a small spiny-rayed fish with potential as a new Acanthomorpha model fish: II. Establishment of a microinjection procedure for genetic engineering.

Rainbowfish is a clade of colorful freshwater fish. Melanotaenia praecox is a small rainbowfish species with biological characteristics that make it potentially useful as an experimental model species. We anticipate that M. praecox could become a new model used in various fields, such as ecology, evolution, and developmental biology. However, few previous studies have described experimental set-ups needed to understand the molecular and genetic mechanisms within this species. We describe detailed procedures for genetic engineering in the rainbowfish M. praecox. By using these procedures, we successfully demonstrated CRISPR/Cas-mediated knockout and Tol2 transposon-mediated transgenesis in this species. Regarding the CRISPR/Cas system, we disrupted the tyrosinase gene and then showed that injected embryos lacked pigmentation over much of their body. We also demonstrated that a Tol2 construct, including a GFP gene driven by a ubiquitous promoter, was efficiently integrated into the genome of M. praecox embryos. The establishment of procedures for genetic engineering in M. praecox enables investigation of the genetic mechanisms behind a broad range of biological phenomena in this species. Thus, we suggest that M. praecox can be used as a new model species in various experimental biology fields.