Feeding Fish Correctly: Preventing Problems in the Aquarium

Fish food is an essential yet often underestimated factor in aquarium care. It does not simply provide nourishment for ornamental fish. When used incorrectly, it can become the source of a wide range of problems within the tank. The connection between these issues and the food itself often goes unnoticed. Many aquarists struggle with persistent problems such as algae growth without realising that their feeding habits may be the underlying cause.

However, without addressing the root of the problem, there can be no lasting solution.

Low quality flake food made from poorly selected ingredients, often purchased in large containers and stored for extended periods, can lead to significant issues. Unsuitable fish food may result in unhealthy fish, reduced lifespan and an increase in unwanted organisms such as snails and algae.

The link with snail infestations

A commonly shared recommendation, particularly in online forums, is to reduce feeding when snail populations increase. While this may help in some cases, it does not always resolve the issue. Even small amounts of unsuitable food can lead to excessive waste. If fish are unable to properly digest and utilise the nutrients, a large portion is excreted back into the aquarium. This waste provides an abundant food source for snails, allowing them to thrive. As a result, the fish may not receive sufficient nutrition, while the snail population continues to grow.

Algae growth and fish food

The same principle applies to algae. Nutrients that are not absorbed by the fish are released back into the water and act as fertiliser for both plants and algae. Adjusting fertilisation or adding CO2 will have a limited effect if poor-quality food continues to be used. As long as excess nutrients are introduced through feeding, algae problems are likely to persist.

Fish food and cloudy water

Cloudy water is often caused by bacterial blooms, which typically appear as a whitish or milky haze rather than a green or brown tint. If the cause is unclear, placing a white object behind the glass can help to identify the colour more easily. Bacteria, like algae, depend on available nutrients, and poorly digestible fish food provides ideal conditions for their growth. High quality food with easily utilisable nutrients can therefore help to prevent bacterial blooms and maintain clear water.

How to recognise high quality fish food

A good fish food is clearly labelled and provides a transparent list of ingredients and raw materials. It should not contain inexpensive fillers or artificial attractants. Flavourings are sometimes used to mask inferior ingredients that fish would otherwise reject. It is also important to consider that fishmeal is not suitable as a primary ingredient for all species. Most aquarium fish are omnivores that feed on a varied diet of insects, plant matter and algae. Even carnivorous species such as bettas do not prey on other fish in nature but feed on worms, insect larvae and small crustaceans.

Hard versus soft food

Very hard granules can damage the sensitive mouthparts of fish when bitten, which may lead to infections. Soft granules are much closer to the texture of natural food and help to reduce the risk of injury, making them a more suitable option.

Which food is suitable for which fish?

Omnivorous species

Providing appropriate nutrition in a community aquarium can be challenging. Fortunately, many commonly kept species such as guppies, neon tetras, angelfish and various catfish are omnivores and thrive on a balanced combination of plant and animal-based ingredients. Dennerle Complete Gourmet Menu is one example of such a balanced, soft granulate. It does not contain fishmeal, and the nutrients are processed in a way that allows efficient absorption and reduced waste.

For enhanced colour development, Dennerle Color Booster contains astaxanthin, which supports the natural pigmentation of fish.

For smaller species such as tetras, danios, barbs and even guppies that may struggle with larger food particles, Neon and Co. Booster offers a finer granulate. It provides high-quality insect protein alongside plant-based components, meeting the dietary needs of small omnivorous fish.

Guppy and Co. Booster is also designed for omnivores and includes natural colour-enhancing ingredients as well as beta-glucan to support the immune system. Its higher proportion of plant material reflects the natural feeding habits of guppies.

Cookies Special Menu by Dennerle is formulated for bottom-dwelling omnivores such as Corydoras, loaches and other catfish. These fast-sinking chips ensure that these species receive their share of food, even in the presence of more active surface feeders.

Specialist feeders

In addition to omnivores, many aquarium species have specialised dietary requirements. Siamese fighting fish, for example, are strict carnivores and do not consume plant matter in their natural habitat. A diet that contains too much plant material can cause digestive issues, as their intestinal system is not designed to process it. In severe cases, this may even lead to illness or a shortened lifespan. While live and frozen foods are suitable options, Betta Booster provides a practical dry alternative if freezer space is limited or feeding live food is not practical. While it does contain a small proportion of plant material, this is significantly lower than in standard fish foods. The inclusion of plant components reflects natural feeding behaviour. In the wild, bettas do ingest plant matter indirectly through the gut contents of their prey, which typically feed on algae and similar sources. Betta Booster by Dennerle is also well-suited for gouramis and other labyrinth fish.

In addition to omnivores, many aquarium species have specialised dietary requirements. Siamese fighting fish, for example, are strict carnivores in the wild and do not graze on algae, not even occasionally. A diet that contains too much plant material can cause digestive issues, as their intestinal system is not designed to process it. In severe cases, this may even lead to illness or a shortened lifespan.

Dennerle Pleco Menu is designed for algae grazing catfish such as Ancistrus and other loricariid species. It contains wood fibres to support digestion, as well as vegetables and algae. A small proportion of animal ingredients reflects their natural intake. The firm structure encourages natural grazing behaviour and provides enrichment.

Goldy Booster is tailored to the nutritional needs of goldfish, which require a balanced ratio of plant and animal ingredients. It is suitable for a wide range of varieties, from standard forms to ornamental breeds such as Lionhead, Shubunkin and Comet.

Cichlids represent another diverse group with varying dietary needs. Some species primarily graze on algae, while others are more predatory. Dennerle addresses these differences with Cichlid Veggy for herbivorous species and Cichlid Carny for carnivorous species.

Discus, often regarded as demanding aquarium fish, are also catered for with Diskus Soft. This soft granulate mimics the texture of natural prey and is readily accepted. It provides a balanced composition of animal and plant based nutrients, using aquatic protein sources rather than mammalian ingredients, which are considered less suitable.

Olibetta is proud to partner with Dennerle to offer a carefully selected range of high quality fish foods. Choosing the right food not only supports the health of the fish but also contributes to the overall balance and stability of the aquarium.

Enjoy your aquarium!