Green Bugs in aquarium

[RoyChavez1017]

Hello,

i have a shrimp and snail only tank. There’s these green little bugs in the substrate. Does someone know what they are? And if they are dangerous to my shrimp and or snails? Thanks!

[JJenna]

They look like they could be springtails, I used to get them in my terrariums. They are good tank cleaners eating plant waste (or in my case any mold that developed in the terrarium). Completely harmless. 

[knee]

Those look like Hydra. 

I read that they could eat baby shrimp.

Edited February 21, 2023 by knee

[knee]

On 2/21/2023 at 4:06 PM, Plantdude said:

i thought hydra looked like this:

 

Yes and they could also look like this 

[RadMax8]

You’ve got hydra. They can grab shrimplets. If you want to kill them, squirt a little hydrogen peroxide on them. If you squish them or scrape them off, they will regenerate. 

[RadMax8]

On 2/21/2023 at 7:11 PM, Plantdude said:

the bugs in the picture look like bugs, they are not that long, and have legs spread out, not all in one area.

I may be wrong, but I believe they are attached to the glass we are looking through, so we just see a green dot and some “legs”. Towards the right side of the photo there are some classic hydra shapes. 

[knee]

All of these are hydra. The ones on the left that look a bit chunkier (kinda look like aphids) are just contracting their bodies.

Edited February 22, 2023 by knee

[RoyChavez1017]

Thank you all for your comments. Will they kill my shrimp? Should I try to get rid of them? My tank is about a month old. 

[mynameisnobody]

After seeing the green ones, I’d harvest them into a separate aquarium and see if I can feed them out to larger fish. 

[Guppysnail]

These are hydra. There are many varieties. I keep 3 kinds intentionally. The small green ones have never nabbed any shrimplette in mine. Even new hatched shrimplettes are too big. My big chunky monkey white ones will though. Over feeding and fine floating foods will encourage them. Buy a feeder dish for your shrimp to contain the food. Stop any type of bacter ae or floating foods. They will cyst up and can be siphoned out. 
The green ones are green because they have a symbiotic relationship with algae. The algae gets nutrients from hydra and the hydra gains from nutrients algae byproducts. 

[AllFishNoBrakes]

Agreed with the others that it’s hydra. I’ve used a dog dewormer on them to get rid of them before. I’ve also just left them, fed less fine foods, and with no food to support them they die off. 
 

Hydra are often found in shrimp tanks where the shrimp will not eat them and you feed lots of fine foods. I agree that a food dish for the shrimp can help prevent fine floating particles which the hydra feed on. 
 

Overall, they’re part of an ecosystem. I’ve never personally seen them eat any shrimp but I bet ones big enough could eat a baby shrimp. Many ways to get rid of them if you don’t enjoy having them.