I've been watching Echo, the Amazing Color-Changing Betta, swimming around the tank half she shares with Ruby for a while now, and I don't think she sees too well. It's not bad when she's swimming slowly, but she aspires to be the boss female of the two, and that's when I start noticing things.

Echo keeps "charging" at Ruby, trying to nip her fins, but she consistently misses, overshooting or running smack into the tank wall. During chases, she runs into the tank plants, the log ornament, and even the tank heater. If it's there, she's run into it.

There are more hints at feeding time that she can't see very well. The pellets I feed are the floating type, and when she tries to grab them off the surface she misses far more often than she catches one. When they finally sink to the bottom, she finds them by doing her best impression of a cory cat, cruising along the tank bottom and snapping them up as she runs into them.

If her vision is that bad I don't think Echo will be able to go back into the main sorority tank; she'd never be able to compete for food with the other females if she can't quite see what's going on. They'd tear her to pieces before she saw it coming. At the moment she shares half of a divided 5-gallon with Ruby, who's an active but docile she-betta.