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Cherry shrimp death and hydra outbreak - help please.


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TL;DR - I had a shrimp become paralysed and die with no obvious red flags and stable water parameters. I found about 10 hydra and would like to know if I can treat with LCA Planaria Fix without harming my shrimp, particularly my berried shrimp and new shrimplets.


Hi everyone,

First, let me say thanks to everyone for all the info on this site, especially Jayc and sdITBfanUK for your many years of patient advice, you've already helped me more than you know!

I am a new blue cherry shrimp keeper and everything had been going pretty great for me shrimp-wise. I have a 41L/9 imperial Gallon tank which I cycled/matured for about 6 weeks before adding shrimp (the tank cycled in 2 weeks, but I left it a bit longer). I then got 11 blue cherry shrimp 7 weeks ago and as I said, everything had been going pretty well. 5 of my females matured and berried with what looks like a lot of eggs, and the shrimp always seemed happy and normal. 

About 1.5 weeks ago I found 1 dead male shrimp which looked almost stuck in the substrate at the back of my tank. It had turned white/pinkish by the time I found it and I have no idea how long it took for me to find. I wrote it off as everything else seemed fine. Then 2 days ago I saw what looked to be Scutariella on a few of my shrimp, including 2 of the pregnant ones. There was 1-3 little white things sticking up from their noses that seemed to move independently. So I salt dipped the affected shrimp, which cleared the obvious white things and the shrimp all seemed normal. Then yesterday I found a shed with some eggs still attached to it. I believe they were from my first female to become berried due to their colour, she had been berried for about 4 weeks. I thought that it may be from the salt dip. 

Things got worse that evening when I found one of my shrimp upside down, apparently dead. I went to get it out of the tank and it attempted to swim around before falling back to the substrate. It looked as though its body was paralysed, but its extremities could still move. It otherwise appeared fine, and had nothing obviously wrong with it. I put it in a small container with clean, prime-treated water as I had read of some people having a similar thing happen due to either toxicity or lack of oxygen. I also topped up the tank and threw in a small sponge filter to increase aeration in case (I don't think it was that as all the other shrimp and snails were acting normally). The afflicted shrimp's movements decreased until I thought it was dead, then about 1 hour later it appeared to be increasing its movements and even flexed its tail a few times but then movement decreased again and it actually died.

My tank parameters have been stable the whole time my shrimp have been in there, and I was wracking my brain trying to work out what could possibly have happened. Tonight I found about 10 tiny hydra in my tank and I am wondering if there is a possibility that the dead shrimp could have been stung by a hydra? Especially if she had just moulted? She may have been the one that lost the eggs, but there is another shrimp with similar markings that I have seen wandering around with no saddle, and as all my females have been either berried or saddled the last week or so, I thought that that one was probably the female that shed her eggs. There were some other moults as well though.

My tank parameters are:

Ammonia and Nitrite: 0

Nitrate: 5-10ppm (this is what they are constantly, and I struggle to tell the two apart, if anything the colour was a little lighter)

Temp: 22 celsius

Ph: 7.2

Gh: 8

Kh: 3

TDS: 210

Phosphate: 0.25

I use a thermometer, TDS and a Ph metre, salifert phosphate test kit and API liquid test kits for everything else. 

I have been doing about 20% water changes once a week and slow drip the freshwater in. I use tap water (and this is what the shrimp were raised in) treated with prime. I have plants, driftwood, dragon stone, Indian almond leaf and a small piece of cuttlebone. These things have all been consistent since the beginning (I added the cuttle bone after cycling to slightly increase my Ph and its been very stable since. I use LCA shrimp safe all-in-one fertiliser at about .75 of the recommended low light dose twice per week, Seachem advance, and 1/8tsp LCA potassium sulphate added at water change. I was due to change water today, so I do not think it is that. All the other shrimp seem happy and normal. I did rearrange the tank about 2 weeks ago and got rid of some Vals that were spreading everywhere and looking scraggly and added a couple of new plants. There has been a bladder snail boom over the last week or so and brown dust and a little green spot algae on the glass.  I have been having issues with getting the plants to grow nicely, but there is still a decent amount of growth. 

I should also mention that I get chemical triggered migraines and so there are no spray chemicals of any kind in the house, and am extremely careful of scented products and any chemical use, so I don't think anything could have gotten into the tank. I have kept frogs (who are very sensitive to chemicals) for 8 years with no mishaps.

In good news, my first shrimplets were born today, I have seen at least two :), so it has been a roller coaster! I have some LCA Planaria fix as I found one hydra (bigger than the current ones) just before adding my shrimp. However, after removing that one I could not find any trace of more despite daily careful checking, so I held off on treating. Would it be ok to use that now? I can't seem to find what the actual ingredients are. I am worried about hurting the shrimplets and the berried shrimp, but obviously hydra are a danger to them as well. Please help :). 

I think I put in all the necessary info, sorry for the long post, thanks for sticking with it if you kept reading :).


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Welcome to the forum and I am pleased you have found it useful so far.

I haven't used the LCA planaria (it maybe an Australian product) but looked it up and it claims to be shrimp/plant safe! I expect the Hydra came in on the plants, as mine did when I set it up. I expect the snails came in the same way?

I don't see anything wrong otherwise, quite the opposite as you have very good parameters. I would try and use as few fertilizer orr other additives though!

The dragon stone should/will raise the PH with time, what substrate are you using? Plants will take a bit of time to settle in and get established properly.

Moults are usually triggered by changes in the water so it is possible that that is why the berried shrimp moulted when treated in the salt bath. You could reduce the weekly water changes to nearer 10%!

Hopefully there are many more shirimplets than you have seen so far in there somewhere?


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Thank you so much for your help. I needed someone to convince me to use the Planaria fix ?.

It seems to have been a great success! I added a 3/4 dose to the tank last night, I mixed it in a cup of tank water then added in, mainly near the filter intake and where the most Hydra were. I was careful to make sure no shrimp were where I poured it in. Within 3 hours the hydras' tentacles were shrivelling up. This morning, the hydra all appear to be dead, they are still attached, but shrivelled up and stumpy tentacles. I poked one to check and it didn't recoil at all, so I am presuming it is dead. Nothing else in the tank seems affected at all. All the snails and copepods seem to be there still (I was kind of hoping some of the snails might get taken out ?). And most importantly, I have seen many shrimp and several shrimplets all happily grazing as normal this morning ?. I saw at least one of the berried females, and she seems fine. There is no evidence of anything untoward.

I will do the bottle recommended 50% water change today. I'll update on any changes/effects. Then hopefully if anyone else is looking for info on this product there can be something to find ?.

Do I just leave the dead hydra to eventually fall off/rot away while keeping an eye on parameters? I don't think it would be possible to remove them physically.

In good news, I saw 7 shrimplets last night, so I have at least that many in there ?. I can't get over how small they are! 

Thanks, I will keep in mind about the dragon stone raising Ph if/when it starts to rise. I am using Carib Sea eco-complete (not a huge fan). I will also look at reducing my water changes. I struggle to know how much I should vacuum up the waste and decaying plant matter. I assume some is good as it provides plant food and biofilm etc. but feel weird leaving too much and also struggle to vacuum around the plants without pulling them out. There seems to be so much poop with the shrimp and snails! Should I basically do the 10% changes, siphoning a section of the gravel and any obvious dirty areas each time and keep an eye on parameters to see if I need to increase on that? I remove big/obvious leaves etc.

Thanks again ?

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3 hours ago, Shrimps&Frogs said:

I will do the bottle recommended 50% water change today

Make sure you gravel vac. Any planaria/hydra dead in the substrate will continue to create ammonia. So getting rid of it with a gravel vac is extremely important.

3 hours ago, Shrimps&Frogs said:

I struggle to know how much I should vacuum up the waste and decaying plant matter. I assume some is good as it provides plant food and biofilm etc

As above, do as much gravel vac as possible after medications are used. 

On a longer term basis, use your Nitrate readings as an indication. If you start to struggle to maintain Nitrates below 20, than a gravel vac can help. And when it become visibly unsightly, a light gravel vac is good, that mean only vac the first 1cm of gravel. Skim the surface.

Like Simon, I don't see anything alarming with your water parameters. GH could be lowered to about 7 if anything. Just to rule out moulting issues. Which means cutting down on ferts for a while. 


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