What To Do With A Puny 10G Tank

[myenigmaself]

I've got a spare 10g tank and I have grandiose plans to hook it up to my 84g setup (55g main tank, 29g sump). Basically the outflow from my main tank would go into the 10g, then I would have another overflow in the 10g that goes back into the sump. All in all it would be a 94g system, nice and stable, with three separate habitats

So I'm trying to think of things I could do in keeping with my current 1.005sg setup. Immediately mudskippers came to mind (in which case it would really be more like an 87g system). Specifically those of the Indian dwarf mudskipper variety (Periophthalmus novemradiatus). Is 10g just too small for a species only mudskipper tank? I've read the indian dwarfs get along decently when you mildly overcrowd them, but I would think they still need their space. Any thoughts on that? Should I just try to convince my better half that we really "need" another fish tank that's bigger? I'm not sure how well that would go over. And then I'd still have the problem of what to do with the 10g.

Any advice would be appreciated Thanks!

 

[kiriyama]

Shell Dwellers, biassed

 

[myenigmaself]

I wouldn't be averse to an invert tank, although that's basically what I've got in my sump. MTS and I'll be having another go at breeding RCS in the near future.

What exactly were you thinking for the 10g? Fiddler crabs or something?