Shrimp Deaths

[Taylor]

Hi All 

I have got an established cherry shrimp tank with 4 assassin snails, it has four air driven sponge filters and is well planted with big bits of moss and bog wood.

I bought the colony about a year and half ago and all has been well lots of young.

In the last month I have lost about 20 shrimp, 3 to 4 a night!

I have kept up my normal 10% water change every other week no change.

so today I went to 2 different aquatic centres that stock shrimp and got them to do water a test for me. Both tests came back perfect, no reason for deaths at all!

what is going on?

Any help would be very apriciated, the only conclusion I have come to is too much interbreeding, as I haven't added any new shrimp for a wile.

 

Taylor 

 

Edited July 13, 2016 by Taylor

[zn30]

Are the ones that are passing from the original batch as they rarely live past the 2 year mark, or are they younger ones do they show signs of difficulty in moulting? 

Do the assassin snails have enough food, unsure if they would prey on shrimp if their food source has depleted.

[ineke]

@zn30 There was an item on FB that showed an assassin snail killing a full size shrimp.

[zn30]

3 hours ago, ineke said:

@zn30 There was an item on FB that showed an assassin snail killing a full size shrimp.

@ineke wow after reading your reply watched some on YouTube, easy pickings is what they like. Even though some get away they more than likely died from shock.

[jayc]

10 hours ago, Taylor said:

2 different aquatic centres that stock shrimp and got them to do water a test for me. Both tests came back perfect, no reason for deaths at all!

Perfect for Fish shops does not necessarily mean it's good for shrimp.

Did you note down what water parameters were tested and what their result is?

My LFS also stock shrimp, but they have no idea what ideal water parameters are for shrimp. They are keeping the shrimp they sell in water with 200+ TDS. I tell them that this is not good for the long term health of the shrimp, and the admit that they never test TDS. Only the usual pH, GH, KH tests.

 

Do you see any abnormal signs of moulting issues or blemishes on the shells that might indicate disease?

 

Do you replenish minerals?

What do you add to your water changes? And do you use tap, rain or RO water?

 

Sorry for all the questions. It helps give us an idea of what the issue might be.

[KeenShrimp]

Hi @Taylor,

This is seriously shooting from the hip, but you sound like you need help ASAP:

Based on the death rate, it might not be viral. ( unless you added new shrimp in the last 2 weeks?)

we are assuming you have not added any decor, new ferts etc to the tanks.

Your tank has been running over a year, so it might be bacterial, due to imbalance in the ecosystem, based on your death rates.

Have you looked at the shrimp carefully to see if anyone is showing signs of illness? In the infection and disease guide they usually show the obvious ones, but not the subtle diseases...The dark organs behind the eyes ( small one on top of head is the stomach, but the fleshy brown-red largest organ is the hepatopancreas). If you have some of the RCS with lower quality colour, you can have a look at the hepatopancreas through the shell: light pink to yellow is sign of infection, usually bacteria. If some of the shrimp have a slight colour loss and slight/small white spots throughout the shell, it might be Microsporidium/Myxosporidium ( I am trying to identify this but it is extremely hard and this is speculation at this stage based on experience)- in this case the shrimp might appear normal and have foraging eating behaviour, but it is easy to spot the affected shrimp as they 'forage' like zombies in the same spot without moving at all for at least 5-10 minutes. Can you see the intestine/ digestive tract through the shells? If so, is it filled with waste or is it empty?- a good way to check if a shrimp is ill.

Do you have measures for controlling accumulation of organic wastes in your tank? You cannot measure this with TDS: you might need to do a thorough substrate vac without stirring up organic waste into the water column.

I would highly recommend doing a thorough gravel-vac with a water change and adding Dr Tim's Eco-Balance probiotic( freshwater one) at full dose to outcompete potential pathogens. There is anecdotal evidence on Quorum -sensing that might shut down pathogens or just outcompete them for nutrients and territory. Regular bacterial supplements for shrimps won't help in this case as they grow/divide to slowly- you need a probiotic to outcompete pathogens fast if you potentially have a bacterial outbreak. 

If you manage to identify sick shrimp, isolate them immediately. Treating shrimp is risky and once a shrimp exhibits symptoms their fate is usually sealed, but there are treatment options mostly once we know more of what you are dealing with.

[Taylor]

Many thanks for everyone's help on this, I decided to remove the 4 assassin snails and it's been 48h with no deaths.

I hope others see this post and remove them before they devastate somone else's colony.

 

taylor 

 

[zn30]

On 15 July 2016 at 8:15 PM, Taylor said:

Many thanks for everyone's help on this, I decided to remove the 4 assassin snails and it's been 48h with no deaths.

I hope others see this post and remove them before they devastate somone else's colony.

taylor 

I think that's a good decision, I like the snails however I'd only employ them in a tank that is ready to be decommissioned prior to redoing a tank to hopefully kill most of the other snails, I don't have assassins so not a problem for me.

[NoGi]

They move so much slower than shrimp, hard to imagine that they are taking out cherries unless the cherries were on their last leg anyway? I'll have to check out that video of one killing a shrimp. Either way, sounds like you got it all sorted now.