Feeding your fish well: more than just a matter of appetite!

As soon as you approach the aquarium, the fish become excited and swim up to the surface. They know it’s feeding time! A few flakes or pellets fall into the water and disappear within moments.

But just because a fish eats eagerly doesn’t necessarily mean its food meets its needs. Depending on its composition, the diet can influence its growth, colour and even reproduction.

So, what should you really look for when choosing the right food?

Not all fish share the same menu

Algae, plants, small invertebrates… In the wild, fish diets vary considerably from one species to another.

These differences are reflected in their nutritional needs. A mainly herbivorous fish does not have the same requirements as a carnivore, particularly when it comes to protein, fat and dietary fibre.

A fish may therefore really enjoy a food without it meeting its nutritional needs. Appetite alone is not enough to tell whether a food is suitable!

Colour also starts with diet

Can diet make your fish’s colours more vibrant? Yes, in certain species, thanks in particular to carotenoids, pigments naturally found in some algae and small crustaceans.

When supplied through food, these pigments can be absorbed by fish and help intensify certain shades, particularly yellows, oranges and reds.

This is why some fish foods contain astaxanthin, a carotenoid used to promote pigmentation, or spirulina, a cyanobacterium that provides various nutrients and pigments.

But these foods do not magically create new colours! They can enhance certain natural shades without changing the fish’s genetic characteristics. Age, physiological condition and keeping conditions also influence colour intensity.

Needs that change with age

A young, growing fish does not have the same needs as an adult.

To build its tissues and develop, it needs an adequate supply of protein and essential amino acids. Fats, vitamins and minerals also play an important role.

In adults, nutritional needs can change, particularly during breeding periods. An appropriate diet then helps meet the demands of egg production and the development of reproductive functions.

The key is therefore to choose food suited not only to the species, but also to its stage of development.

Flakes, pellets, wafers: form matters too!

Imagine a fish that naturally searches for food at the bottom of the aquarium while its entire meal floats on the surface.

Even food with an excellent nutritional composition is of little use if the fish cannot eat it properly.

Flakes suit many fish that feed near the surface or in midwater. Depending on their formulation, pellets may float, sink slowly or reach the bottom quickly.

Sinking wafers and tablets are particularly useful for certain species that search for food on the substrate.

Size matters too. A pellet that is too large may be difficult for a small fish to swallow, while food that is too fine may disperse before it can be eaten.

And watch how much you feed! Even quality food can cause problems when given in excess. Uneaten food decomposes and can contribute to poor water quality.

Should you vary their meals?

In the wild, fish do not necessarily encounter the same food every day. Their diet can vary with the seasons, available resources and their environment.

In an aquarium, a quality complete food suited to the species can serve perfectly well as the basis of their diet.

However, other suitable foods can also be offered: plant-based foods, frozen foods or small prey, depending on the fish’s feeding habits.

This variety can encourage different food-searching and prey-catching behaviours while providing a range of textures and foods.

But variety does not mean choosing more products at random. A varied diet is not automatically more balanced: it all depends on what each food provides and the fish’s actual needs.

What about the next meal?

The next time your fish rush towards their food, take a few moments to observe them. Some take food from the surface, others wait for it to sink, while bottom dwellers search for their meal on the substrate.

These behaviours already offer valuable clues about their feeding habits.

But beyond their appetite, it is the composition of their food that deserves our attention most. Proteins, vitamins, fats and pigments such as carotenoids each play different roles, and their effects vary according to the species and its needs.

Food enriched with spirulina or pigments therefore does not, on its own, guarantee more vibrant colours or a better diet.

Ultimately, feeding your fish well means choosing the food that truly suits them, rather than the one that promises the most.