I would be wary of mixing them with a synspilum. V. sysnspilum can be quite territorial and aggressive depending on your individual fish's attitude. If you do try this I would keep an eye on the pbass and make sure they're not being attacked/harassed. As far as feeders go, that's open to debate, personally I feed my frozen food soaked in vitamins. Feeders can contain disease/sickness and introduce to your fish, if you quarantine/gutload your feeders you'd be alright. Just remember though that once they become accustomed to feeders that's all they will want and are very stubborn when it comes to eating anything else. So that means going to your LFS on a very regular basis to buy feeders or you could raise feeders on your own...