Redeyed tetra

Question
Hi Brittany-

My red-eyed tetra is acting very strange today. i've been noticing he's losing scales and today it looks like part of his top fin is falling off. i don't believe it's a case of another fish hurting him, because there's only one other fish in the tank right now, (the other fish is a guppy, his "partner" tetra just died.)

Any ideas on what could be happening?
Thanks!
Erin

Answer
Erin,
It sounds like your fish may be flashing. If you have ever noticed your fish rubbing itself on rocks, decor, or anything else that is most likely the case.
Flashing can be caused by many things, including temperature changes, parasites, water quality changes, high pH or low pH, or bacterial infections.
The most common cause of flashing is a pH which is not to their liking, or a parasite problem. Among the parasites, the most common are Flukes and Trichodina.
Stabilizing the pH is a good idea to relieve flashing behaviors caused by pH changes or a low pH.
Killing off Trichodina can be accomplished with aquarium salt in many instances. Flukes can be controlled by several methods including SupaVerm and Fluke Tabs. Follow all instructions to a T because most fluke remedies are toxic if overdosed or left in too long.