Active shoalers that colour up with age
Rainbowfish
Rainbowfish are peaceful, energetic shoalers that ship as drab juveniles and reward patience — full colour can take a year. They want swimming length, a real group, and (for the larger species) harder, more alkaline water than most community fish.
5 species on Finfern · 5 with a full care guide.
💧 Get the water right: Give them horizontal swimming length and a shoal of 6–8+; check hardness — larger rainbows dislike soft, acidic water. Care model: Tropical community tank
- Boesemani Rainbowfish Melanotaenia boesemani A farm-bred beauty that ships drab — hard water, a real shoal and a year of patience make the fish on the box.
- Dwarf Neon Rainbowfish Melanotaenia praecox The dwarf neon fits small tanks but not small groups — a real shoal in soft light is where the electric blue shows up.
- Threadfin Rainbowfish Iriatherina werneri A stunning but delicate nano: mature calm tank, gentle flow, tiny food, no fin-nippers, and a shoal of 6+.
- Celebes Rainbowfish Marosatherina ladigesi A shimmering yellow-finned gem — stunning in a shoal, but a soft, sensitive fish that wants clean, harder, rock-stable water.
- Madagascar Rainbowfish Bedotia madagascariensis A silvery, red-finned schooler with real presence — an underrated, hardy rainbowfish for a spacious community.
Plan a rainbowfish tank
Our free tools use these species' real, sourced care data — no guessing:
Stocking calculator → Compatibility checker → Which fish suit your water? →