Freshwater Fish Diets: Carnivores, Herbivores & Omnivores
Match food to species — carnivore, herbivore, and omnivore diets for community tanks, cichlids, catfish, and specialty freshwater fish.
Freshwater fish diets
Not all fish eat the same food. Carnivores need protein-rich meaty foods. Herbivores need plant matter and algae. Omnivores — the majority of community fish — thrive on a balanced mix. Feeding the wrong diet causes bloating, poor colour, and long-term health problems.
Diet types
| Type | Examples | Primary foods |
|---|---|---|
| Carnivore | Bettas, puffers, most cichlids | Bloodworm, brine shrimp, pellets, frozen meaty foods |
| Herbivore | Otos, plecos, silver dollars | Algae wafers, blanched veg, spirulina pellets |
| Omnivore | Tetras, rasboras, guppies | Quality flakes/crumble + frozen/live treats |
| Micropredator | Killifish, small tetras | Live or frozen baby brine, daphnia, small pellets |
Food formats
See food types for a full comparison of flakes, pellets, frozen, live, and gel foods.
- Flakes & crisps — surface and mid-water feeders; lose nutrients quickly once opened
- Micro pellets & granules — sink slowly; good for tetras and barbs
- Sinking wafers & tablets — bottom dwellers and nocturnal species
- Frozen foods — bloodworm, brine shrimp, daphnia; thaw in tank water before feeding
- Live foods — enrichment and conditioning; quarantine to avoid introducing parasites
Species-specific notes
Community tetras & rasboras
Small mouths need fine crumble or micro pellets. Supplement with frozen daphnia or baby brine 2–3 times weekly for colour and conditioning.
Cichlids
African rift cichlids often need higher vegetable content than South American species. Match protein level to species — mbuna are more herbivorous than peacock cichlids.
Catfish & plecos
Not all "algae eaters" live on algae alone. Otocinclus need constant biofilm; common plecos grow large and need substantial vegetable and protein. Feed sinking wafers after lights out.
Goldfish & fancy varieties
Use sinking gel or pre-soaked pellets to prevent swim bladder issues from gulped air. High vegetable content supports digestion.
Feeding routine
Follow the 2-minute rule — only feed what is eaten in two minutes. Most adult community fish do well on 1–2 small meals daily with one fasting day per week.
Common mistakes
- One flake for every fish — plecos and otos starve on flake alone
- Overfeeding protein to herbivores — causes bloat in mbuna and plecos
- Dry pellets without soaking for fancy goldfish and bettas — swim bladder risk
- Ignoring nocturnal feeders — add sinking food after lights out
Frequently asked questions
How do I work out what my fish eats if the shop did not say?
Mouth position is the quickest tell: upturned mouths feed at the surface, downturned mouths graze the substrate, and forward-facing mouths usually hunt. Gut length is the other clue — herbivores have long intestines suited to plant matter, carnivores short ones. When in doubt, the species page in the fish knowledge base states the diet.
Can one food serve a whole community tank?
A quality staple covers most omnivores, but a mixed tank rarely thrives on a single food. Bottom dwellers cannot compete for flakes at the surface, and dedicated herbivores lose condition on a protein-heavy diet. Rotate a staple with a sinking food and something green.
How often should I feed?
Once or twice a day for most adult community fish, in amounts eaten within two to three minutes. Fry and small, fast-metabolising species need more frequent, smaller meals. Uneaten food is the most common hidden nutrient source behind algae problems.
