I have 100 Gallon Brackish tank
2 Knight Gobe's
3 Monodactulus Sabea's
2 Green Spotted Puffers
1 Figure 8
I've noticed recently that my Figure 8 and one of the Green Spotted Puffers are staying at the top of tank. They dont look stressed and seem to be breathing fine. Just for insurance I put a second water filter to turn up the water more and there is good distance between the filter and water level so it works well. I also have 2 Airstones. Im cycling the tank 5 times and hr. I also did a 20% WC
yesterday and nothing has changed. One of my puffers is super happy swims through all the bushes and looks like he is having a blast but im concerned for the other two. No one is attacking eachother, there is plenty of space and plants and rock formations to keep them entertained. I'm at a loss. Everything checked out on my water test kit but I'm going to take a sample to my fish store just to verify. Would anyone know what could cause this? All my other fish are very happy. The puffers do sleep at the bottom but once I turn on the light 2 of the puffers just swim to the top and literally do nothing all day. Its been 3 days now. They both eat still too.