Algae-Eater Loach Ill?

[Doodlez]

I've got a grey chinese algae-eater loach that I've had for a couple of years now. Up until about a week ago he's been quite active but recently he's rarely left his hidey hole at the bottom of the tank, even when I feed the fish, and he is virtually still all the time. So much so that at first I'd thought he'd died but then noticed he was still breathing.
Does anyone have any idea what could be wrong with him?

The other fish in the tank are neons, danios, guppies and a rtb shark, shrimp and snails. I've had a similar selection of fish in the tank all this time so I don't think that could be the problem and there is nothing apparently wrong with the chemistry either (ph~7, temp~26C, no ammonia/nitrate problems).

Any suggestions would be much appreciated.

Thanks.

 

[sXeLifer]

Might be an internal infection have you treated the water with an anti internal bacteria formula. It wouldn't do them any harm to add some and it DEFINITELY works.

 

[fishnovice]

In my experienec CAE are particulrly sensitive to poor water quality and/or lack of oxygen, much more than other fish. When my filter stopped working overnight I found 3 out of 4 CAE dead the next morning but my gourmi, RTBS, raphael catfish and neons in the same tank were unffected

 

[Doodlez]

He seems to have perked up again now. Maybe he just a shy week or there was a brief issue with oxygen, who knows!
Thanks for everyones advice though.