Weird Parasite In Tank

So I noticed there were small dark ovals swimming in my tank water and I caught a few. They have a shell of some kind and seem to be a crustacean or parasite. They aren’t snails. Any ideas?

 

Could be cope pods or triop.

 

Definitely look like snails. But snails don't usually swim. Daphnia?

 

Looks like snails, they can fill with air and float around to new areas faster than crawling.

 

Bladder snails and duckweed are not parasites...

 

Id would of said snails. Why are you sure theyre not snails?

 

They are definitely snails. They were probably not swimming, they were either on the walls or clinging to the ends of the duckweed. Mine do it all the time.

 

It's difficult to say with the quality of those pictures, but if I had to bet, I'd pile on and say snails also- first pic, top right, though just an outline, is in focus and it really looks like a snail. Look at them with a magnifying glass. If we're correct, they may become a problem because of how quickly they reproduce, but they won't hurt your fish.

 

I think they are likely to be Ostracod (Seed Shrimps).

I have had them in one of my aquaria. My Corydoras fry fed on them.

They are a large group of Crustaceans with about 70,000 species currently known.

They are harmless but as they feed on organic matter their presence may indicate an excess of food in the tank.

Usually there isn't usually enough for them to eat so they don't become so numerous that they are a problem.

Many fish eat them.

 

I think they are likely to be Ostracod (Seed Shrimps).

I have had them in one of my aquaria. My Corydoras fry fed on them.

They are a large group of Crustaceans with about 70,000 species currently known.

They are harmless but as they feed on organic matter their presence may indicate an excess of food in the tank.

Usually there isn't usually enough for them to eat so they don't become so numerous that they are a problem.

Many fish eat them.

If they are ostracods they have clam like shells. They have to open their shells when they swim or feed - you may occaisionally see feet or antennae sticking out of the shell. I have a friend that compares their swimming to the flight of drunken bumblebees.