Sidways Pacu

Question
So we has a 70 gallon take at the office and my fish (Paco the Pacu) is swimming sideways. He has done it before and I thought he was just getting a new perspective. But, today it is for longer periods of time. And sometimes he is leaning against the class. He is still small so it in not the tank size, and he doesn't have ich. Any thoughts on what his problem is if his has one?

Answer
Hi Kara,
That sounds like Swim bladder disorder. If you aren't sure what this is - many species of fish have a special organ called a swim bladder. Which controls their balance and swimming to a great extent. If something interferes with this organ, the poor fish will float sideways, upside-down, or sink uncontrollably to the bottom. It is not fatal and doesn't mean a fish needs medication either.

The primary cause is often related to a diet that lacks enough fiber or too much dry food is being fed. Diet problems can cause blockages in the intestine which puts pressure on the swim bladder. Fish can recover on their own, but often they do need help and definitely need an overview of their overall diet.

There are other causes to swim bladder like bacterial infections, injuries, tumors, ect... That can severely affect the swim bladder but there's no need to get into that just yet. They are rather uncommon in comparison to the diet-related swim bladder disorder.

Treatment I would recommend would be to hold off his regular food for at least 1 day. Take in consideration how much variety/fiber he is getting in his diet. After fasting him for a day, feed him a mashed and shelled green pea a few times a day which will help relieve blockages in his intestinal tract. See if you can find any poo in the tank which would signal that he is either not constipated or is getting over it.

Pacu--despite their piranha-like appearance--are actually mainly vegetarians. So problems like swim bladder could affect them more so.

One other thing I would make sure of is that the water quality is good and healthy for him. Test the water or have it tested by a petstore to make sure the Ammonia and nitrites are both ZERO and nitrates are under 20.

If the water quality is ideal and his digestion seems good. Then his behavior might simply be a way of resting or observing the environment. Some fish also lean on their sides if they are unsure about something around them.

I hope this helps and best of luck!
Karen~