We, those in this hobby, are fascinated with the shapes, behaviours and not in the least by the colour of the fish we keep or wish to keep.
To look after our fishes we spend quite a sum on their food, and many come with the words like “Contains natural pigment enhancers to intensify the radiant colours of your fish”………………………… have you ever wondered about what could be these substances? Or if it were of any effect or at all needed???? Or how does the fish colour up? Is the fish in any sort of control over its colouration?
Many fishes do not show any sort of colouration till sexual maturity. We can take it from this observation that the colourings of such fishes are governed by their endocrine hormones.
Then even with fishes who show their colours from a young age, fishes do sometimes look washed out; happens when they are under stress, therefore the pigments giving the colourations are placed on the skin in a way that they can be near the surface to augment the colouration or removed from near the surface of the skin to give the washed off look. This happens in special cell called ‘chromatophores’ which branches away from just below the surface of the skin and are linked to the nervous system. At times of stress the pigment contained in the chromatophores goes into the deeper branches giving the fish the washed out look.
So we should expect good healthy unstressed mature fishes to show the brightest of colours. That is not always the case. The reason for this is that out of the many pigments used by fishes for colouration, some can not be synthesized by the fish, and the fish depends upon the availability of these pigments in the food that they eat.
Pigments like melanin (Brown to black), and crystals like iridophores (Shiny silver) are synthesized by the fish. Fishes cannot synthesize pigments like Carotenes (Orange to red), Xanthophylls (Bright yellow), Phycocyanins (Blue).
To get the fish to look its best we must then see that the required amount of pigment is available in the food we feed the fish. Carotenes are available in, yes carrots but in much superior quantities in salmons and krill. Most green plant food will contain Xanthophylls, but did you know that the bright yellow petals (brackets actually) of marigold and sunflower has the highest concentration of these pigments and dried petals could be incorporated into fish food. For Phycocyanins don’t go looking for blue-bells but look for the villain BGA, yes the Cyno-bacter and remember that spirulina too is a cyno-bacter and can provide this pigment.
Now next time you read those colour enhancing advertisements about fish food you know what it is speaking of – And if like me – you too prepare your own fish food you know what to add to your various formulations.