Aquarium Fish Feeding

Feeding fish seems simple: throw food, they eat. But the truth is that wrong feeding is one of the main causes of problems in aquariums. Excess food pollutes water, lack of variety causes deficiencies, and the wrong type of food can even kill.

The most important rule

Less is more. Fish eat less than you imagine. The classic rule is: offer only what they can eat in 2-3 minutes. If food is left over, you gave too much.

Unconsumed food sinks, rots, and becomes ammonia. Ammonia kills. Beginner aquarists lose more fish to overfeeding than to hunger.

Fish don't die of hunger easily. A healthy fish can go a week or more without eating. You traveling for 3 days don't need an automatic feeder or neighbor throwing food. Leave them without food and it's fine.

Feeding frequency

Adult fish: Once to twice per day is sufficient for most species. Some aquarists prefer feeding once per day, others divide into two small portions.

Fry: Need more meals (3-4 times per day) in small quantities. Faster metabolism, smaller stomach.

Weekly fast: Some aquarists do one day of fasting per week. Helps clean the digestive system and gives a break in waste production. Not mandatory, but doesn't hurt.

Types of food

Flake food

The classic. Floats, then sinks slowly. Good for fish that eat at surface and middle of water column. Loses nutrients quickly after opening (shelf life of 2-3 months after opening, even if package says more).

Pellet food

Sinks faster or immediately (depending on type). Better for larger fish and bottom fish. Maintains nutrients longer than flakes.

Bottom tablets

Specific for bottom fish (corydoras, plecos, botias). Sink immediately and dissolve slowly, giving time for bottom fish to eat.

Freeze-dried foods

Artemia, bloodworms, dehydrated daphnia. Good as treats, not as main diet. Rehydrating before offering is good practice.

Frozen foods

Artemia, bloodworms, krill, etc. More nutritious than freeze-dried. Thaw in aquarium water before offering. Don't refreeze.

Live foods

Live artemia, daphnia, microworms. Excellent nutritionally and stimulates natural hunting behavior. But requires own culture or frequent purchase.

Variety is important

Don't feed only one type of food. Just like humans, fish benefit from varied diet. Alternate between base food, frozen foods, vegetables (for herbivorous or omnivorous species).

Herbivorous fish (many plecos, for example) need vegetables: cucumber, zucchini, shelled peas, spinach. Secure to bottom with a weight or stick.

Carnivorous fish need animal protein. Plant-based food won't nourish adequately.

Practical rule: quality food as base (70%), varied foods as complement (30%).

Food quality

Not all food is equal. Cheap foods often have much filler (low-quality flours) and little real protein.

Look at ingredients. The first items are the most abundant. Fish or seafood protein should be at the top for most tropical fish. Avoid foods where wheat or soy flour is the first ingredient.

Quality foods cost more, but you use less (more nutritious) and produce less waste.

Shelf life: Buy packages you'll use in 2-3 months. Opened food loses nutrients over time, especially vitamins. Storing in refrigerator prolongs a bit.

Feeding specific species

Bettas: Carnivorous. Specific betta food or high-protein foods. Bloodworms are loved. Beware of overfeeding, their stomach is the size of their eye.

Corydoras: Bottom omnivores. Bottom tablets, but also eat leftovers that fall. Don't rely on them to "clean" the aquarium, feed directly.

Plecos: Most are herbivorous or omnivorous. Need wood to scrape, fresh vegetables, bottom tablets with spirulina. Carnivorous plecos exist but are minority.

Neons and tetras: Omnivores, eat almost everything. Small flakes, micro pellets, small live foods.

Cichlids: Varies greatly by species. Research the specific species. Some are strict herbivores, others carnivorous.

Signs of wrong feeding

Water always cloudy or with foam: Probably excess food decomposing.

Obese fish (very large belly, difficulty swimming): Overfeeding.

Thin fish with head seeming too large for body: Undernutrition or disease.

Excessive algae: Excess nutrients (from unconsumed food) feed algae.

Water parameters always bad: Too much food = more ammonia.

Vacations and absences

Short absences (up to 5-7 days): don't feed before leaving "to compensate". Leave without food. Healthy adult fish handle it fine.

Longer absences: automatic feeder (program for small portions) or ask someone to feed (give VERY clear instructions about quantity, people tend to exaggerate).

Vacation blocks? Those blocks you throw in the aquarium and "feed for 7 days"? Most experienced aquarists don't recommend. They dissolve, dirty the water, and fish often don't even eat them. Better to leave without food or use automatic feeder.

Practical summary

Feed less than you think you should
2-3 minutes to consume = right amount
1-2 times per day for adults
Vary food types
Quality food makes a difference
When in doubt, don't feed (for short periods)

Correct feeding = clean water = healthy fish. It's simple when you understand.