Despite the difficulty in keeping these that I have heard from all sources, here is a Red sponge. strikingly beautiful, and seems to be doing ok.
The ONLY issue I have... (This is funny as hell). When I got him, I was watching him on the first day and all of a sudden, he Leaned over 90 degrees... I was taken back. I know they can move, but not THAT fast....
In a couple minutes, he leans back upright... I am completely perplexed...
Look carefully. Notice the "rock" he is mounted to... Its NOT a rock. upon closer inspection the next day I realized.... ITS A BiValve! WTF?!?!