Tropical Fish Care FAQ — Frequently Asked Questions

The ideal water temperature varies by species, but 24–28°C (75–82°F) is a general guideline. Use a heater and thermostat to keep it stable. In summer, temperatures above 30°C (86°F) can be dangerous, so a cooling fan or aquarium chiller may be needed. Place a thermometer where it's easy to read and check it daily. Avoid rapid temperature changes, as they cause significant stress to fish.

Neon tetras, guppies, platies, corydoras, and white cloud mountain minnows are great for beginners. They are all hardy, tolerant of water quality changes, and affordable. Neon tetras are beautiful in schools, and guppies offer the fun of breeding. Check out our Popular Tropical Fish Rankings for more details. Browse actual listings in the Tropical Fish category.

The basic rules for community tanks are: avoid pairing fish with large size differences, steer clear of aggressive species, and diversify swimming levels (top, mid, bottom). Tetras with corydoras is a classic combination. Male bettas must never be housed with other males. Choose tank mates carefully and observe compatibility after introduction. If unsure, consult a breeder through our Tropical Fish category.

Tropical fish food comes in several forms: flakes, pellets, frozen food, live food, and tablets. Flakes are versatile for top-to-mid level swimmers, and tablets suit bottom-dwellers like corydoras. Frozen bloodworms and brine shrimp are highly palatable — offering them 1–2 times a week improves nutritional balance. Feed twice a day, only as much as fish can consume in about 2 minutes.

The standard practice is to change 20–30% of the total water volume once a week. Always use dechlorinated water matched to the tank temperature. Use a water test kit to monitor ammonia, nitrite, and nitrate — change water when nitrate exceeds 40 ppm. For more details, see our User Guide.

Breeding methods vary by species. Livebearers like guppies and platies breed relatively easily. Tetras and corydoras often spawn in response to water quality and temperature changes. Keys to success include nutrient-rich food, spawning plants or moss, and separating eggs or fry from adults. Getting tips directly from a breeder is also highly recommended. Find experienced breeders in our Tropical Fish category.

For a 60 cm tank, a canister filter (such as Eheim) is the top recommendation. For tanks 30 cm or smaller, hang-on-back or undergravel filters are cost-effective. Top filters are easy to maintain and beginner-friendly, but unsuitable for planted tanks as they off-gas CO2. Choose a filter rated for a larger volume than your tank. When in doubt, ask a breeder for advice.

Common diseases include ich (white spot disease), fin rot, cotton wool disease, and Aeromonas infections. The best prevention is stable water quality and quarantining new fish. A common ich treatment is gradually raising the temperature to 30°C (86°F) combined with a 0.5% salt bath. Early detection is the key to successful treatment. If you need help, contact us or consult a breeder.

BreederDirect is planning to expand its tropical fish category. You'll be able to purchase pedigreed and rare species directly from verified breeders, with the escrow payment system ensuring secure transactions. For details, see our User Guide.

Set up a tank in this order: choose a location, install the stand and tank, add substrate and plants, start the filter and heater, cycle for 2–4 weeks (nitrogen cycle establishment), then add pilot fish. Confirm that ammonia and nitrite read zero before introducing fish. Do not skip this cycling period. For more details, see our Tank Setup Guide.