Trilineatus not happy

[Pleco Fan]

My new Trilineatus are not at all happy, one has just died, they are quite lethargic, they move around the tank then just stay put for ages, all my parameters are fine so are the other fish, my ph is 7 so I don't know what is wrong, the water is soft and the last time I bought some of these they were very happy and breeding.

[black ghost]

I thought they looked a bit ropey in the photos, to be fair. Could be from shock from diabolical shop water… or a few things, bacterial, protozoan… It’s always hard to tell when there’s no obvious symptoms.

[Pleco Fan]

Well two have died I'm down to four, It doesn't make any sense, I haven't had any deaths in over eighteen months or so. All the other fish are perfectly happy as usual.
They are still hardly moving around the tank it's just not usual behavior for cory's.

[BigBen]

They're skinny, get some lobster eggs in to them and a good pellets - 50% protein ideally. Water change daily. Do you have a hospital tank you can use?

[plankton]

Melafix and Interpet anti internal bacteria are the best two things for corys with problems, plus the protein/meaty food soaked in garlic.