Which fish is right for me?

Start from the fish, not the bowl. Pick your tank size, whether it's heated or unheated, and whether your tap water is soft or hard — then choose fish that actually fit all three. Plan for the fish's adult size and its minimum tank, check whether it needs a group (most small fish are shoaling and need 6+), cycle the tank first, and always read the full care guide before you buy.

You need coldwater or adaptable species — not tropical fish. From our sourced guides, white cloud minnows are a humane coolwater shoaler (keep 6+, no heater), and several subtropical-tolerant fish (rosy barb, odessa barb, pearl danio, denison barb) suit an unheated community. Goldfish are coldwater too but are very heavy-waste and need a lot of water. Match every fish's temperature band to your tank.

Small tanks suit small, low-bioload nano fish kept as one species rather than a mix. Options from our sourced guides include a single betta, or nano shoalers like ember tetra, chili rasbora and celestial pearl danio — each still needs a group of its own kind. Cherry shrimp and snails also work in small tanks. Enter your tank volume above and the matcher only shows species whose minimum tank actually fits.

Yes. Soft-water fish (many tetras and rasboras) and hard-water fish (livebearers like guppies, platies and mollies) do best in water that suits them, and shrimp and snails need enough hardness to build shells and molt. Test your hardness or ask your water company, then pick fish that match — it's far easier than trying to change your water. Leave it on "not sure" and the matcher won't rule species out on hardness.