Not going to keep repeating what has already been said,
But as far as your puffer goes, i'm going to guess its either a GSP (Green Spotted Puffer)
or an F8 (Figure 8) Puffer
If its a GSP, then it will eventually need full marine conditions as it matures, and around a 30G tank for a single specimen... can be very aggressive and will likely pick on any tankmates... although they are also very slow growers...
If its an F8, then its a very light brackish water fish, much less aggressive, although will still likely pick on any tankmates and does best in around 15-20G if solo...
Also as mentioned, puffers teeth may require trimming if not taken care of, so feeding them hard shelled food diets such as home bred crays, of feeding deforsted frozen Mussels or Clams can help with wearing teeth down... be sure to keep at least the half shell on for them to wear their teeth against...
Eitherway, i do agree that possibly selling off all your stock on hand first, and then planning everything properly BEFORE purchasing more fish might be a good idea... since as with many of us, in the past when we first started out i'm sure we have either lost fish due to cramming too many of the wrong types of fish together, or bought fish home that will eventually grow too large for the tanks we own...
And with your stock its basically trouble waiting to happen... Especially when you consider Plecos / Puffers are known to be huge waste dispensers, so without adequate filtration and some knowledge of how to maintain a healthy tank, you may see problems with things such as Ammonia, Nitrates and Nitrites among other things such as aggression...
-EDIT-
Also, waiting till a fish grows too large to house before selling is not always a good idea... since if we are to be honest, a lot of people who aren't hardcore fish keepers will think a 30G is huge, so waiting till the fish no longer fits in your tank before selling it will make it seriously twice as hard, and chances are no one will want that big fish any more, since it doesn't look all cute and cuddly like when it was a mere 2"-3"
But as far as your puffer goes, i'm going to guess its either a GSP (Green Spotted Puffer)
or an F8 (Figure 8) Puffer
If its a GSP, then it will eventually need full marine conditions as it matures, and around a 30G tank for a single specimen... can be very aggressive and will likely pick on any tankmates... although they are also very slow growers...
If its an F8, then its a very light brackish water fish, much less aggressive, although will still likely pick on any tankmates and does best in around 15-20G if solo...
Also as mentioned, puffers teeth may require trimming if not taken care of, so feeding them hard shelled food diets such as home bred crays, of feeding deforsted frozen Mussels or Clams can help with wearing teeth down... be sure to keep at least the half shell on for them to wear their teeth against...
Eitherway, i do agree that possibly selling off all your stock on hand first, and then planning everything properly BEFORE purchasing more fish might be a good idea... since as with many of us, in the past when we first started out i'm sure we have either lost fish due to cramming too many of the wrong types of fish together, or bought fish home that will eventually grow too large for the tanks we own...
And with your stock its basically trouble waiting to happen... Especially when you consider Plecos / Puffers are known to be huge waste dispensers, so without adequate filtration and some knowledge of how to maintain a healthy tank, you may see problems with things such as Ammonia, Nitrates and Nitrites among other things such as aggression...
-EDIT-
Also, waiting till a fish grows too large to house before selling is not always a good idea... since if we are to be honest, a lot of people who aren't hardcore fish keepers will think a 30G is huge, so waiting till the fish no longer fits in your tank before selling it will make it seriously twice as hard, and chances are no one will want that big fish any more, since it doesn't look all cute and cuddly like when it was a mere 2"-3"
