Hi everyone. 

I am new here so I hope you can help.

I have got a community fish tank that has been running (fully cycled) since the beginning of May. In addition to my fish I added 11 red cherry shrimp. All seemed fine. My shrimp were active, feeding, moulting and a couple of the females were developing saddles. 

2 weeks ago everything changed. I discovered one of my shrimp had a white patch on her. On closer inspection it looked like a hole. All of the shrimp went into hiding and became less active and then they all started dying. Some of them seemed to have the same white patch but some didn't. I removed the bodies of my last 2 shrimp yesterday.

Ammonia and nitrites are 0. Nitrates are between 20 and 30 (they come out of the tap at 20). pH is 7.6. I don't know water hardness but I know we live in a hard water area.

Water changes are 25-30% every week.

My fish are fine. Whatever it is has only affected my shrimp. 

This all started when summer finally arrived in the U.K. and the tank temp increased. Heater is set st 24C but in the heat the tank crept up to over 25C.

I hope someone might have an idea about what has killed my shrimp and how to make sure my tank is safe before reintroducing shrimp.

Sorry for the long post. Thank you all for your help.

 

 

  

 

 

 

Edited June 19, 20178 yr by Kat129

Cannot see the shrimp in the first pic in great detail. Are both pictures of the same shrimp?

Never seen anything like that. It has a pattern that is almost worm like.

Are all the white patches in the same spot?

Any possible chance the fish are eating them?

 

 

Temps are on the high end but they wouldn't cause that... unless the shrimp are molting more often, meaning their shells are softer, then the fish go after them? Although that seems rather uniform in size...

They are different shrimp.

The patches seem to appear in roughly the same place. Some of the dead shrimp didn't have them though and some of them have simpy vanished without a trace.

It is very odd.

 

Get a liquid GH and KH test kit (i.e. API, Sera, or? must be liquid!), and if you can swing it, a TDS meter. (calibration solution if you want to make sure it's accurate)

 

I don't know how much they cost over there, but here they are pretty cheap. This will help tell us what could be going wrong.

very odd! It looks like something sucked the shell  o.O

I have seen fish take chunks out of shrimp if the shrimp is too big for the fish to eat whole. They constantly worry the shrimp , pull legs off etc . Even in the best planted tanks shrimp are at risk. Usually it happens after lights out when the shrimp tend to come out and graze. If you can't find anything else keep that in mind - not many fish are truly shrimp safe which is why I got rid of all my fish in the end ?

Tend to agree with @ineke there. RCS can get on fine with your fish for a long time but when the fish get hungry, if you forget to feed for a few days, they then become food. Once the fish have worked out that shrimp taste good then they are forever in hiding.

What type of fish do you keep in the community?