Dying baby shrimp?

[zlh850]

Hi,

I’ve had a 5G tank of 20 opae ula for the past 9 months now. I set up the tank following the instructions on the website and have been letting it run with no tech other than a light as per recommendations on here.

However, they seem to be refusing to multiply, and when one shrimp does get berried things seem to go wrong. My last berried shrimp was around 3 months ago- I counted 8-10 floaters in the tank, but as far as I can tell only 3 of those survived to become juvenile shrimp.

I just had two more shrimp become berried, and one had the eggs hatch a couple days ago! However I quickly noticed something concerning- the “floaters” are instead “sinkers”. There are easily 15-20 of them, but all of them are sitting on the substrate, only jumping up briefly when an adult shrimp almost tramples them and then drifting back down to settle on the substrate again. They don’t seem to move smoothly- instead mostly relying on violent tail kicks to move around with seemingly no destination in mind.

I’m worried the babies of this batch and the next will end up dead, does anyone have any suggestions? I’m a bit confused as to how the adult shrimp can end up happy, healthy, and active, but almost every baby dies.

I tested my water, the parameters are:
Salinity- 1.010
Ammonia, nitrites, nitrate- 0
Ph- 8.2

The only things in the tank are seiryu stone, fine black gravel, and the two types of macro algae sold on this store. Nothing new has been added to the tank since the shrimp were added 8 months ago, and I haven’t fed the shrimp anything for almost 2 months, as they seem to be subsisting fine on biofilm and are mostly disinterested in any food I drop in, only coming over for a couple nibbles then swimming off.

[Rosiepink89]

Maybe a contaminant is in the water at low enough levels that adults are ok but babies are not? When I had contaminant enter my tank my smallest guys got sick first.

[Rudiarose]

Turn off light wait about 10 mins then flip them on and see if you got any of the bad worms I have heard about. They eat baby shrimp's. They hide when lights are on. They come out when it is dark. You might be able to spot them better if you surprise them. Can you do a live action video up close so we can see if we might spot them for you?

[Vorteil]

Really? This is the first I’ve ever heard of this. Do you have any references for this? Interesting so I’m curious.

[Rudiarose]

https://www.youtube.com/watch?v=okhpITV ... ShrimpLife

This video, shows a few pests that can hurt your shrimp's and how to get read of them.

[zlh850]

Update: the larva are still just laying at the bottom of the tank, but at least some of them are surviving since I now have much more shrimp than before. I wouldn’t think it’s the water quality since they aren’t just dying, and Im pretty sure planaria only exist in freshwater tanks. How would I go about posting a video here? It only seems to allow pictures.

[Harry]

The video posted above is for freshwater shrimp. I doubt those pests would survive brackish water.

Your photo shows a post-larvae shrimp, rather well developed. If they are laying at the bottom of the tank, there might be a water quality problem. I have baby shrimp that size and they are quite active and feeding off the algae and biofilm. I suggest checking for ammonia, nitrates, nitrites, pH and salinity, etc. I am not an expert here but others can suggest the specific tests.