The Puffer Forum

No, it dips inwards just under its fin.

Yes, Raphael, I see that, but it also goes back out again, and overall the puffer doesn't look thin.

Thats what I am concerned about. It dips in then goes back out. My other F8 is perfectly rounded.

Like I said, as long as he is overall in good shape, and keeping weight on, don't worry. People have different curves too.

It could be somewhat like LisaLisa says, fish individuality. My one F'8 has a similar body line (and similar markings as well) to yours, eats well, is active and survived what ever caused his tank mate to die(both bought and introduced at the same time, both showed signs of illness at the same time), the other is nearly a perfect torpedo (and markings so different I thought it was a different species-dark back markings so large-it covers 80% of his back/sides-no little green/yellow lines on the sides or between circles,like yours and my other display)
As long as he is active, eats, colors don't fade(one that died went albino first), mid line of his body does not look like a gray line, and his belly is white (Although these are generally signs of stress, not necessarily indicators of specific illness) it may not be that serious (yet??)- I mean things aren't bad enough for the fish to start to worry about it (no signs of stress)- as long as he is not losing weight, things may not be as bad as you think, Take it for what its worth-as someone with a fish similar to yours-I have little experience with internal parasites(both in my fish and personally :33: ), and have not had my f'8's much longer than you..if one of the Guru's says it is something worse, I will likely be trying the same remedy..