New Jurupari laying low

I bought a pair of juvenile (2.5in) Jurupari two days ago and I'm concerned about their behavior. Since adding them to the tank, they've acted generally stressed (dark coloration) and shy. They've taken little of the food I've offered them (pellets, bloodworms) and mostly just lay near the bottom of the tank. Now I've never owned this species, and have read that they can be pretty mellow, so is this just what they are like when first added to a tank? At the store they ate readily and seemed active. There is no other fish in the aquarium. I'm performing a water change after this post.

Thanks, I took your suggestion and added the only other fish I have (female swordtail) to the tank. I'm going to get more swordtails in the future. It seems to have helped somewhat. Each day they are getting a little bolder, but still seem not quite right. I also think that they may be S. daemon, and not S. jurupari. They have two black spots on their side, which none of the jurupari pictures (even the juveniles) have. Could I really have gotten S. daemon? I bought them at a local petco (yeah I know). I usually wouldn't buy their fish but these looked particularily nice, and my petco manages to keep a decent selection of sw and reef stuff alive, so I figured why not.


If they really are S. daemon (and I'll try to get pictures soon, but they still are really shy), what should I do to get my tank in check? My pH is about 6.5.

Well one of the two died today and I'm pretty sure the other's days are numbered. I'm confident at this point that they are infact S. daemon. Here's a blurry picture for reference.