..think it would work?? It is a 55 gallon corner tank. I used to have a large peacock mantis and it lived happily with a clownfish. But a spearer is a bit different. It's only 2 1/2 inches long. I haven't fed in in a few days because I don't want him to get used to being stick fed too much. I want to actually see the guy. So now his burrow is covered back up and the cardinal fish that was in there seems to be gone.......hmm. Anyhow, they had a nice Whitley's boxfish at my LFS, small one. They are very curious fish though, so my judgement says no way. It has been documented that smashers can live together wish certain fish, can the same be applied to spearers ??