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Guides

Each guide is a single-question filter on the fish library. Which fish nip fins. Which outgrow a 60L within a year. Which actually behave themselves in a community of mixed species. Numbers on each row come straight from the profile pages, so the lists move when a record changes.

Pick the guide closest to your question. Use it to get from “all 115 fish” down to four or five names that fit. Two of them go into the pair checker for the head-to-head. The whole shortlist goes into the tank builder. Guides will not stock your tank for you. They tell you which fish are worth checking properly.

  • Beginner-friendly freshwater fish

    The "beginner" label means routine: forgiving of a missed water change, tolerant of a five-degree pH miss in week one. It does not promise the fish will fit your tank, your existing stock, or your shoaling group. Pick two or three names from the list and check those questions on each profile before you spend.

  • Peaceful community fish

    Every fish here lacks any aggressive, semi-aggressive, or predatory flag in its data. That is one screen out of about five. Wrong volume, wrong pH band, or a half-stocked schooling group will still make two "peaceful" species hide from each other or stop eating. Pair-check anything you actually want to put in the same glass.

  • Fin-nipping fish

    Nipping is mostly a group-size and layout problem. Six tiger barbs in a 100L with real swim length keep their teeth on each other. Two of them in a 60L with a betta will denude the betta in a week. Stock the proper group of one species and stay away from long-finned tank mates: bettas, fancy guppies, angelfish, anything with veil fins.

  • Aggressive & semi-aggressive fish

    These species carry an aggressive or semi-aggressive flag. They need volume above their listed minimum, plant cover or rockwork that breaks line of sight, and a stocking plan that often comes down to one species per tank. The order you add fish matters too: an established cichlid will defend its half of a tank against any newcomer, regardless of size or temperament label on the newcomer's profile.

  • Fish that may eat smaller tank mates

    Mouth size at purchase is not mouth size at six months. These species are flagged predatory, or as likely to eat small fish, or both. Plan around adult gape, not the polite juvenile you saw in the shop. Anything that fits in the mouth is potential food. That includes shrimp, snails, fancy guppies bought small, and the fry of anything that breeds in the tank.

  • Fish that grow too big for small tanks

    The species here either need a lot of water on day one, or grow into a lot of fish over a year or two. Both groups outrun starter tanks. The minimum litre count on each record is the floor for a stable adult life, not the smallest tank the fish can survive in. A 30 cm fish is still a 30 cm fish in 200 litres if the tank is only 80 cm long.

  • Schooling & group fish

    Either a schooling flag is set on the record, or the group minimum is above two. Under-schooled fish look sick. They hide, they nip, they ignore food. The same species in a proper group of eight behaves like a different animal in the same tank. Buy the whole group at once whenever you can. Adding two more later rarely fixes the stress already imprinted on the first six.

  • Fish for smaller aquariums (on file)

    Each species here has a small enough minimum volume and a small enough adult size to live in a nano tank. That does not make a nano tank a community tank. The same 60 L still has one filter, one heater, one volume of oxygen, and one footprint to fight over. One schooling species, or one pair of a slightly larger species, is usually as far as a 60 L should go.

  • Often shrimp-tolerant (heuristic, conservative)

    This list is the intersection of four flags: peaceful temperament, no predatory marker, no fin-nipper marker, and an adult size small enough to make adult cherry shrimp an unappetising mouthful. None of that is the same as shrimp-safe. Every fish here will still pick off shrimplets in a sparse layout, and most will go for a moulting adult that drifts into open water. Mature the tank, plant it heavily, and add the shrimp first.

  • Fish that are a poor first choice for beginners

    Each species here carries one of: a "not recommended for beginners" flag, an "advanced" care level, or an aggressive temperament in a body big enough to bite back. Most first failures with these fish are equipment failures, not fish failures. The page also surfaces a shorter alternatives list above the species below. Almost every aspirational fish here has a hardier relative that teaches the same skills before it teaches them by dying.