Tank bred? Those are really rare, as T. biocellatus seems to breed independent of the owner, and thus we can't figure out what makes them do it. In fact, the only tank bred T. biocellatus I've ever seen was $25US each, because of the rarety. No T. biocelatus stays at 2 inches. I've kept them in pure FW and had them grow to just over 5 inches. Others have gotten them to the same size in brackish water. Also, puffers produce a lot of waste for their size. Roughly 3-4 times the amount of wast. They are also messy eaters, which leaves more food to decay in the bed. Even T. biocellatus can be aggressive as well. They are generally good natured, but not always.
I've also had Brachygobius sp. become puffer food before.
Just because I'm new to this forum, doesn't mean I'm new to fish keeping or that I don't know what I'm talking about. I've got tons of posts on other forums as well, and I've been keeping fish as long as I can remember.