sorry to hear of your sick fish. i removed a neon dottyback not long ago. i went to my LFS, great guy he is, let me borrow his fish trap. all it is is a 4" diameter cylinder. the back closed off, the opposite side is a slide door tied to a fishing string. put some food in the back of the cylinder, the fish went in, let go of string and door slides down trapping fish.
of course, i caught everything but the dottyback at 1st, but he eventually came curiously in the trap.
hope this helps and keep an eye on those other fishes
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