Tiny brown creatures in my aquarium

[JMC]

I have discovered some tiny (less than 1mm) brown creatures in my aquarium. They seem to like to swim just above the mulm layer. I also saw a lot of them on the foot of a dead bladder snail (not sure if they killed the snail or found the snail after he died).  They are most numerous in my scud aquarium. 

 

They swim around some and seem to be attracted to light. The closest thing I can find online that looks like them is referred to as “water mites”.

 

Any help identifying them and advice on if they are harmful to fish, scuds or snails would be greatly appreciated. 

[Tlindsey]

On 3/2/2024 at 1:07 PM, JMC said:

I have discovered some tiny (less than 1mm) brown creatures in my aquarium. They seem to like to swim just above the mulm layer. I also saw a lot of them on the foot of a dead bladder snail (not sure if they killed the snail or found the snail after he died).  They are most numerous in my scud aquarium. 

 

They swim around some and seem to be attracted to light. The closest thing I can find online that looks like them is referred to as “water mites”.

 

Any help identifying them and advice on if they are harmful to fish, scuds or snails would be greatly appreciated. 

 

On 3/2/2024 at 1:07 PM, JMC said:

I have discovered some tiny (less than 1mm) brown creatures in my aquarium. They seem to like to swim just above the mulm layer. I also saw a lot of them on the foot of a dead bladder snail (not sure if they killed the snail or found the snail after he died).  They are most numerous in my scud aquarium. 

 

They swim around some and seem to be attracted to light. The closest thing I can find online that looks like them is referred to as “water mites”.

 

Any help identifying them and advice on if they are harmful to fish, scuds or snails would be greatly appreciated. 

@JMC looks like seed shrimp.

[Chick-In-Of-TheSea]

Hmm, seems I have had those before. Mine were scuds. 🙂
They didn’t really swim, they just ran around.

 

Edited March 2 by Chick-In-Of-TheSea

[Biotope Biologist]

I 2nd seed shrimp. Harmless little tank cleaners. Evidence suggests they pass through fish intestines completely unharmed so they will persist 

[JMC]

Thanks for the information. I will research seed shrimp more. Would seed shrimp kill a snail?  I assume they’d eat it if it was dead.  Are seed shrimp considered a type of water mite?
 

They are too round in my opinion to be baby scuds (although I wish they were).

Edited March 3 by JMC
Grammar

[JMC]

Here is a short video of them swimming in a puddle of water. 
 

[Chick-In-Of-TheSea]

On 3/2/2024 at 2:34 PM, Biotope Biologist said:

Evidence suggests they pass through fish intestines completely unharmed

That’s kinda crazy

[Biotope Biologist]

On 3/2/2024 at 12:11 PM, JMC said:

Thanks for the information. I will research seed shrimp more. Would seed shrimp kill a snail?  I assume they’d eat it if it was dead.  Are seed shrimp considered a type of water mite?
 

They are too round in my opinion to be baby scuds (although I wish they were).

Seed shrimp are ostracods they will eat any decaying matter and detritus. They are usually a sign post of a healthy aquarium ecology