get some raphy cats platidoras costatus they are fun readily available I love mine. they body shape isnt very RTC like.
and if you could get ahold of them I really want some but microglanis iheringi they are SA drift wood cats and that particular species stays small. also somthing I would get againg not very RTC like but JOhn has 4 for 20 dollars are honey comb cats
other than those nothing comes to mind