Is it possible for some fish to shrink?

[Turin Turambar]

I have noticed today that my Ramirezi seems smaller than before.

I guess other fish, like Neons grew bigger and now poor Ramirezi looks smaller. He eats normally and is healthy.
It's probably illusion, but can the fish shrink (with no some obvious illness)? Thanks.

[ChilDawg]

They can, but it's usually not uniform along all dimensions...that is, their stomach shrinks...but the rest of them doesn't usually do so.