Colour is the worst reason to choose a betta, because colour survives conditions that damage almost everything else. A fish can be vivid and still be exhausted, underfed, or carrying the early signs of a problem that clean warm water at home may or may not reverse. Work through the fish instead: how it holds itself in the water, the condition of its fins and body, the clarity of its eyes and the rhythm of its gills, and finally how it behaves when it notices you. Passing on a beautiful fish that fails those checks is not fussiness; it is the discipline that keeps a new tank healthy from the first day.
Posture, Swimming, and Body Shape
Start by watching the fish without tapping or crowding the container. A sound betta holds itself upright and level, hovering comfortably rather than tilting to one side, listing head-up or head-down, or resting constantly on the base. Watch it swim: it should move to different depths with easy fin strokes, hold its chosen level without sinking, and right itself promptly if it turns. A fish that struggles to stay up, sinks tail-first, or floats involuntarily at the surface is showing you a problem, whatever its colour promises. Then judge the body's shape. From above and from the side it should look smooth and gently full behind the head, not pinched or hollow behind the gills, which suggests it has not been feeding, and not swollen or pineconed, with scales lifting away from the body, which suggests a serious internal problem a vet would need to investigate.
Fins, Skin, Eyes, and Gills
Move to the surface details once the posture passes. The fins should open fully rather than staying clamped tight against the body, and their edges should be clean: look for tears and splits, blackened or ragged edges, white spots dusted across the fins or body, and any fuzzy or cottony patch, each of which is a reason to pass and choose another fish. The skin should look smooth, without raised lumps, open sores, or patches where scales are missing. Check both eyes: they should be clear, bright, and the same size on each side, not cloudy, bulging, or sunken. Finally watch the gills for a full minute. Both sides should open and close in an even, unhurried rhythm, with no flared gill cover stuck open, no redness at the edges, and no rapid panting in water that is not visibly foul.
Behaviour: Response, Curiosity, and Feeding Interest
A healthy betta notices the world. Move your hand slowly near the container and watch for a response: the fish should turn toward the movement, follow it, or flare briefly. A fish that sits on the bottom and ignores repeated gentle movement, or one that darts in panic at the slightest shadow and cannot settle, is telling you it is not coping well in the shop. If staff are feeding while you visit, watch whether this fish rises and eats, because a betta that competes for food in a shop container has reserves and confidence working in its favour.
Making the Final Choice
Narrow your choice to two or three fish that pass every check, then choose between them on temperament and the look you enjoy, because health has already done the hard sorting. Note the fish's starting condition before you leave: fin shape, any tiny imperfection you accepted, its energy level, and whether it fed. That baseline matters, because a month from now you will judge this fish against photographs and memory unless you wrote it down while it was fresh. Take the fish straight home, acclimate it patiently into its heated, cycled tank, and let it settle before you judge its colours again under your own light. KinsLe's Pet Passport gives that day-one baseline a permanent home alongside the betta's source and diet, so any later change in fins, appetite, or energy can be compared against how the fish truly started.