Thirty gallons is the working minimum
Plan on 30 gallons or more for a blue gourami, and favour length over height when you choose the tank. Blue gouramis — the blue colour form of the three-spot gourami — grow into substantial fish, deep-bodied and several inches long, with long, trailing pelvic fins they use almost like feelers. A fish that size in a small tank has nowhere to establish the loose territory it naturally claims around the surface and upper plants, and crowding is the most common reason a gourami gets a reputation for bullying: tankmates cannot leave its patch because there is nowhere else to go.
In 30 gallons and above, with planting breaking up sight lines, a single blue gourami usually settles into a dignified, cruising presence rather than a tank tyrant.
Layout: surface, shade, and escape routes
Gouramis are labyrinth fish that breathe air at the surface, so the top of the tank is their home territory and should be designed for them. Floating plants or tall plants reaching the surface create the shaded, still corners a male may choose for a bubble nest and give the fish cover where it spends most of its time. Keep filter flow gentle at the surface; a strong outflow constantly breaking up the top water works against everything a gourami wants to do there. Leave open gaps among floating cover so the fish can always reach the air.
Through the middle and lower levels, plant in clumps with swimming lanes between them. This broken layout lets smaller tankmates slip out of the gourami's sight line, which defuses most territorial moments before they become chases.
Choosing companions for a gourami's tank
A blue gourami's tankmates should be peaceful, mid-sized, and not inclined to nip those long trailing fins — fin-nippers will worry a gourami relentlessly, and very small, delicate fish may be treated as food by a large adult. Keep one male gourami unless the tank is genuinely large and heavily planted; males are territorial with each other, and a pair in limited space often means the weaker fish lives in hiding. Bottom dwellers that keep to the substrate generally coexist well, since the gourami's interests stay in the upper half of the water.
Add the gourami after shyer tankmates have settled where possible. An established gourami views the whole tank as home; newcomers introduced to settled smaller fish usually fare better than the reverse.
Feeding and everyday condition
Blue gouramis are unfussy omnivores that feed at the surface and mid-water, taking floating foods readily and investigating almost anything offered. Feed a varied staple in amounts cleared within a couple of minutes, and make sure food is spread so tankmates below the gourami's territory also eat. A healthy blue gourami shows deep, even colour and those long pelvic fins intact and flowing; faded patches, fin damage, or a fish hanging listlessly at the surface away from its usual spots are cues to check water quality first — test before treating — and to watch whether a tankmate conflict is the real cause.
Regular partial water changes and a varied diet keep this hardy fish in condition for years.
One set of details for everyone helping
Gourami tanks run into trouble when one person feeds generously, another rearranges the surface plants, and a third adds a new fish nobody planned for. KinsLe Family Sharing keeps your blue gourami's profile and care information visible to the family members who help, so everyone works from the same stocking plan and the same feeding notes.