The genes responsible for gold and gold marble colors are primarily responsible for the yellow and orange hues in angelfish.

If a fish displays yellow, orange, or shades of these colors, it likely carries one or both of these genes.

Marble may also contribute some color, but significant coloration generally indicates the presence of gold or gold marble genes as well. While genetics determine the potential for color, they do not dictate the exact amount of color visible on each individual fish.

1. Epigenetics

Epigenetics plays a key role in determining the amount of color potential in angelfish, particularly after decades of selective breeding with numerous orange fish. It’s believed that epigenetics is the main factor influencing this variation. Genes can remain dormant or be expressed depending on an epigenetic marker attached to them. These markers are influenced by the environment and the coloration of the parent fish.

This is why breeding the best specimens is crucial: while it’s not possible to directly breed for more gold genes, you can increase the number of epigenetic markers and better control how easily they are expressed. Without careful selection for these traits, each generation may show progressively less color. Epigenetics explains the wide variation in color seen in fish with gold or gold marble genes.

2. Environment

The environment you provide directly influences the epigenetic expression in angelfish. By managing stress levels, you can turn the expression of genes on or off. Poor environmental conditions lead to poor color, while good environments encourage vibrant coloration, and optimal conditions yield even better results!

Water: Water quality is crucial. If your tap water is poor, it will be difficult to achieve good color. While the specific elements of ideal water are not entirely clear, different water types can lead to varying color outcomes.

Food: Nutrition plays a vital role in coloration. First, food must contain carotenoids, the compounds that fish store in their skin and which express as yellow/orange colors. Fish cannot produce these pigments on their own and must ingest them. Even if you don't intentionally color feed your fish, carotenoids are found in almost all foods, and without them, the fish won’t express any yellow/orange hues.

Stripeless Gene: Angelfish have multiple skin layers, with the carotenoid layer located beneath others. The stripeless gene plays a key role in making these stored pigments visible. When homozygous, the stripeless gene creates a translucent top layer, allowing underlying pigments to shine through more clearly. The brightest, most vibrant pigments are visible in fish with the most translucent skin.

3. Fish Husbandry

Proper fish husbandry is crucial for maintaining healthy, colorful fish. Regular water changes, fewer fish per gallon, careful feeding, and minimizing stress are all important. Stress can arise from many sources, and it's impact on color may not always be immediately obvious. Often, fish show signs of stress through color fading, so if fish appear unstressed but lack vibrant color, it’s likely that stress is present but not easily recognized.

4. Age

Young fish typically have less color, and their coloration is more susceptible to change. As they mature, the color becomes more stable and less likely to improve or degrade. However, excessive stress can still cause color loss.

5. Buying Fish with Color

If you purchase very young fish (under 2 months old) without much color, you may be able to enhance their coloration over time, but they will never reach the vibrancy of fish that already have significant color. If young fish come with excellent color, stress can easily cause them to fade.

The best option is to buy older fish that already display vibrant color, as they are less likely to lose it compared to younger fish. Keep in mind, though, that acquiring fish with great color does not guarantee it will remain that way.

When stressed, the fish's immune system uses carotenoids as antioxidants, depleting the pigments that would otherwise contribute to their color. It’s important to avoid this by minimizing stress and allowing the fish to store carotenoids for vibrant coloration.