Paralyzed pleco

[SryImABiologist]

could it be some type of internal parasite? if it was ammonia poisoning i would expect the smallest fish to be damaged first and with how tough plecos are it really surprises me. test your water for lead and mercury, could cause neurological damage which may cause paralysis like symptoms.

 

[Nigel_K]

Sorry for the radio silence. I took Oscar to a great vet a week ago to find out that his poop basically consisted only of worms in addition to a bacterial infection...with the outbreak most likely caused by the ammonia poisoning.
He was treated at the vet and we treated him here for the last couple of days. Unfortunately he died today. But he fought a long fight for 3 weeks. So did the guppy Nate, who died last week as well. I wish I could have helped them more.
Thank you very much for your kind help and your suggestions.

 

[coralbandit]

Sorry you lost your fish.
Are you still or did you treat the tank as well?

 

[Nigel_K]

Thank you very much! Yes, we treated the tank as well. We even had antibiotics shipped, but it was too late.
We still have our otocinclus Herman in the tank. He hides most of the time, but every now and then he comes out and darts around. We are so glad that we still have him.