Aquarium Fish for the Planted Tank, A Complete Guide

Small, peaceful, plant-safe schoolers dominate the planted-tank canon: neon tetras, cardinal tetras, ember tetras, harlequin rasboras, chili rasboras, celestial pearl danios, pygmy corydoras, and otocinclus. Centrepieces include German blue rams, Bolivian rams, honey gouramis, and sparkling gouramis. Avoid known plant-eaters (goldfish, silver dollars, large barbs) and notorious shrimp predators if you're keeping a shrimp colony.

The 'one inch per gallon' rule is unreliable, adult size, body shape, bioload, and swimming style all matter more. Better starting points: a 60-litre tank supports 8–12 small schoolers plus a centrepiece, a 120-litre supports two schools plus a pair of dwarf cichlids, and a 240-litre opens the door to larger rainbowfish and apistogramma communities. Use Fin & Stem's per-species 'minimum tank size' field as the floor, not the goal.

Schooling fish swim in coordinated, tightly-spaced groups (cardinal tetras, rummy-nose tetras). Shoaling fish gather loosely for safety without coordinated movement (most rasboras, livebearers). Both need numbers, 6 minimum, 10+ preferred. Single fish or pairs from these species are visibly stressed and short-lived.

Most tropical fish need 22–28 °C, a heater is mandatory unless your room sits in that range year-round. A handful of temperate species (white cloud mountain minnows, zebra danios, paradise fish, hillstream loaches) tolerate 16–22 °C and can run unheated in a stable room. Always size the heater at 1 W per litre minimum and use an inline thermostat for redundancy.