Cherry Shrimp experts opinions needed on a dwindling shrimp colony.

[GoYankees10]

I have a 20 long cherry shrimp tank that has had a very successful colony the last 20 months.  In it are Shrimp and snails.  The snails I have used the e to feed my pea puffers and through entire time I have always seen lots of baby shrimp.    The last month- 2 months or so I’ve noticed I haven’t seen any babies and the colony has gone from tons to maybe 15 shrimp.  Plus all the snails that where in it are dwindling also with no smaller snails anymore.    Parameters all seem good, nothing has changed.  I never have missed a bi weekly water change and I have fed them the same the entire time.  Any advice welcomed.   

[Trish]

Wonder if these questions would be something to consider.......Are you feeding them enough?  Do they have supplemental calcium?  Water changes too large?  I'm still learning but doing well with mine at the moment. Usually if snails dwindle they are not being fed enough to populate.

Taken from AquariumBreeder.... 

As your shrimp colony grows, sometimes an imbalance in sexes can cause a problem. If you have too many males in the tank when the female is molting, the males will do this “happy dance” and kind of frenzy around the whole tank looking for that female. 

Sometimes when there are too many males they overwhelm the female. It stresses her out and can kill her.  This is something to keep in mind. When you have a really large colony you notice that your female shrimp are turning up dead.

Do you watch for hydra, they will eat shrimp-lets.  

This is interesting... didn't know that the shrimp-lets can starve out competing for food with the adults.    

https://aquariumbreeder.com/how-to-increase-shrimplets-survival-rate/

Also check tank temperature.. higher temps will promote breeding but they won't live as long. 

 

Edited May 27, 2021 by Trish

[Ken]

Look close to see if you have Planaria. My "breeding for profit" shrimp tank recently had a Planaria population explosion. They killed almost all of the snails and put a serious dent in the shrimp. I ended up using Panacur C to clear them out. It's been a couple months and the tank is just recovering. There are a bunch of articles and videos about it.

[GoYankees10]

I have never seen any type of worm In the tank.   

[Stealth Aquatics]

I feed a shrimp pellet, green beans, xtreme sinking water, occasionally blood worms. And mine are thriving. Are you feeding enough? I have a 5 gallon upstairs that I threw some cherry shrimp in with my betta and they don’t get target fed and they won’t multiply in population. My breeding tanks explode in population because I feed them heavy. I do about a 30% water change weekly. My water parameters are ph7.2-7.4 gh 7 kh 3-4. I keep them at 76-78. I also keep a tank at room temp to slow them down. I hope this helps. 

[Guppysnail]

I had the same problem in a tank where I had such a prolific shrimp population I gave them away by the dozen and fed guppy fry shrimplets.  Nothing new to my tank in 6 months. First micro rams horns disappeared then bladder snails then shrimplets. Then I started seeing a few bladder snails in front of my tank where there are no plants and they never go there. I found a strange “shrimp” picking at my full grown mystery snail. Netted it and what it was was a Damselfly nymph. As it grew it went from eating micro organisms to micro snails then shrimp. I netted out four total I’m sure there are more because my few remaining micro snails and shrimp all stay out front in the open. I heavy vacuum gravel twice a week now to pull anymore out of the substrate. I keep a close eye on testing in case I disrupt the bacteria. My understanding is dragonfly larvae are even more predatory.  

[Over Grown Aquatics]

Considering its both shrimp and snails declining that narrows it down quite a bit. For both to be effected it has to be food or water quality assuming you don't have any predators in there. If the tank has been successful for 20 months Ill assume that the test results are typical? Personally id want to see the water a bit hard and higher PH but if they were doing well before now that shouldn't be a big deal. Id vary up the diet, maybe spread some leaf litter around for the shrimp to graze on all the time to supplement your feeding 

Edited May 27, 2021 by Nature Coast Aquariums

[Dkshadowwolf]

One other thing to keep and eye on is the actual number of remaining shrimp. I just watched and old video of a round table with shrimp king and he mentioned that you want to have at least 20-30 adult  shrimp to keep a good breeding colony. I would agree if it’s not water quality that it most likely not enough food. 

[GoYankees10]

Thanks for the info everyone.   

[Ken]

When you figure it out will you please post a follow up? I'm sure more of us will encounter whatever it ends up being.

[HenryC]

Maybe check if your water source hasn't changed in anything. Do you use tap water?

[Stealth Aquatics]

I agree with feeding enough. A lot of little shrimp will smash green beans ect overnight. 

[NanoNano]

One good habit I've found is to kill your aquarium lighting early one night every week or two  and then do a sudden lights on "midnight tank check".  You'll probably be surprised to learn that there's things in your tank that you didn't know were in your tank.  Case and point-  I thought my elderly snail was the last Mohican from a batch of 6 I once had.  Did a 1AM tank check last week and counted 14 juveniles in the same tank before they could dive back under the substrate.