Can I keep upside down cats in my 29g?

[Eupterus]

First off, I'd try to find out what kind of upside down cat it is. All synos swim upside down.

 

[Phil22]

I have to agree with highgrovemanor. I have one, and see it about once every two months or so. They hide all day, and come out to feed at night.
So if you're looking for something to "watch", I'd go with something else.

 

[Eupterus]

Maybe it depends on the species. My synos are plenty active during the daytime.
I have a big clay pot in there where they could hide in all day if they wanted to.
The most hiding I see is my alpha sitting in the cave head sticking out. And he doesn't sit there very long before he decides to swim a lap. Sometimes they like to "dance" together.

 

[red devil]

Isn't your tank a little on the full side now?

 

[jpappy789]

That's what I was thinking^

Your going to need at least 3 synos to make them feel confortable, and with 4 corys already, your tank would be crowded at the bottom...