Dead shrimp & EI fert dosing

[qoob]

Hello,

I've added 30 Caridina species during the last 3 weeks in my 120 liter planted community aquarium and I rarely see them. I've seen one shrimp corpse on the aquasoil and just found another near the canister filter intake (sponge). The shrimps that I do see seem active'ish (don't know if they are active or not), but they may be still a bit afraid of their tank mates. I have 2 honey gourami, 9 Celestial Pearl danios, 13 ember tetras and 4 otos with the shrimp. The honey gourami and ember tetra do not seem interested in the shrimp and the danios are too small to be an issue (even though they sometimes look at shrimp from very close, they never try and take a bite).

I'm trying to figure out why I've found dead shrimp in the tank. My water parameters (measured with JBL brand liquid tests) are as follows:

0 ammonia, 0 nitrites, varying nitrates but always under 20'ish. Temperature is at 24.5 celsius.
To be safe, measured copper which was at undetectable levels. Iron was at 0.15.
CO2 injected in the tank for the same time as lights are on (with 1,5h offset). CO2 was a bit high a week ago (lime-green/yellow'ish drop checker) but tuned it down (green drop checker).

From tap pH is 7.5, KH 1.5-2 and GH is 2.5-3.
Tank pH sways between 6.4-6.8 depending if CO2 is on or not.
Substrate is ADA aquasoil + I have driftwood.

The odd part is that for some reason KH and GH in the tank have risen up. KH is 3 and GH 6.

I dose according to the estimative index daily, using an auto dosing pump. It pumps a total of 10ml of Aqua Rebell Makro Basic EI in 3 smaller doses along the day. https://www.aquasabi.com/Aqua-Rebell-Makro-Basic-Estimative-Index
I also dose traces, for which I use Aqua Rebell Mikro Basic Eisen and dose a total of 2ml per day in two doses of 1ml. https://www.aquasabi.com/Aqua-Rebell-Mikro-Basic-Eisen-500-ml

Together these add the following nutrients in the following amounts (daily):
3.07 mg/liter NO3
0.57 mg/liter PO4
2.34 mg/liter K
0.15 mg/liter Mg
0.017 mg/liter Fe
0.008 mg/liter Mn
0.001 mg/liter Cu
0.00067 mg/liter Bo
0.0003 mg/liter Zn
0.00067 mg/liter Mo

I tried feeding the shrimp, but they were not interested. Like my otos, they prefer everything else that is found in the densely planted tank.

This is all I know - what I don't know is why I've found 2 shrimp bodies. How do the params etc. look? Could it be a failed molt (to be fair I don't really know what that would look like)? What else could it be if not that?

 

[ZxC]

gH might be a little low. kH should read 0 with aquasoil, how old is the aquasoil?

Sorry to tell you, but your fish are for sure eating the shrimp, or harassing them to death. If your filter intake aren't covered in an intake sponge they will be sucked into the filter.

They are likely hiding a lot too, NO3 is a little high for shrimp, so is temperature.

 

[qoob]

gH might be a little low. kH should read 0 with aquasoil, how old is the aquasoil?

Sorry to tell you, but your fish are for sure eating the shrimp, or harassing them to death. If your filter intake aren't covered in an intake sponge they will be sucked into the filter.

They are likely hiding a lot too, NO3 is a little high for shrimp, so is temperature.

Oh interesting - for some reason I assumed shrimp would like warmer water. I guess I could bring it down to 23 celsius without harming the ember tetra/CPDs who seem to prefer warmer waters.

Aquasoil is 2 months old and kh has never been 0.

Lucky for me, the other fish (with the exception of CPDs) are not interested in the shrimp. Sometimes a single CPD might follow the shrimp around, but usually they just swim by even after following. I don't know what happens during the night, but during the day when the lights are on and the white/red shrimp are clearly visible on the dark substrate the fish don't care. At night time I'd assume they care even less since they can't see the fish. Based on behaviour during daytime everything seems to be OK. By my logic if the issue was fish, I wouldn't find any bodies.

I'm sure the shrimp would be out and about more if it was shrimp only, but 120 liters is a bit much for that . I'm getting a smaller shrimp tank later, but want to understand the current ones better. And I do have a sponge near the intake specifically for this reason, as mentioned in the OP.

 

[Autumnsky]

Which Caridina species are the shrimp?

 

[qoob]

At least Caridina logemanni, Taiwan bees and tigers (caridina mariae)

 

[earhtmother]

Yup I can pretty much guarantee the fish are harassing if not eating the shrimp. I have a 120L tall that was shrimp only that I added 5 Chili Rasboras to, worst mistake I could make. I have hardly seen my shrimp since. The ones that I do catch a glimpse of are quick to hide if they think I am looking. I am hopefully moving the shrimp to their own 210L next week and the rasboras will move to one of my community tanks.

 

[Autumnsky]

Most fish like to eat little things be it shrimp or fish fry, it is just natural behavior, though some don't really bother. Other creatures like shrimp and many small fish are more timid if a "predator" is sharing the tank.

 

[libertybelle]

Also keep in mind that shrimp go through cycles of molting. When they molt they are temporarily distracted and unable to jump away from a fish and then are soft for a while while their new shell hardens. Just because the fish aren’t actively hunting all the time doesn’t change the fact that the species of fish in your tank natural prey is shrimp. Show them a distracted or unprotected/ soft shrimp and they think dinner even if they wouldn’t bother to chase a fully alert shrimp around the tank.

Stressed shrimp die. If you want to keep them together your goal is to create an environment where enough shrimp can survive and reproduce to balance out the deaths from stress and predation.

That means lots of fine leafed plants and moss and a prefilter sponge and even then it’s gunna be tough to keep any babies alive in that tank. Baby shrimp are natures perfect fish food!

The lower temp is a good idea too. Reduced the stress on shrimp to molt so frequently and reduces fish metabolism a bit so they might not be so hungry for a chase

 

[qoob]

This is my tank now https://i.imgur.com/XwrMmmO.jpg
If I get baby shrimps I'm hoping the very thick bush of cryptocoryne wendtii will help them out since it's so dense only shrimp can get in. Also I've got riccardia moss all over the place but don't think that would be of much help...
The shrimp like to stay in the forests on both sides of the tank. The pre-filter Sponge on the back left corner is a popular spot. Also I've seen a bunch of shrimp under the driftwood. Accidentally made it into a cave big enough for shrimp but too small for fish.

 

[libertybelle]

That is beautiful! And with that kind of set up you may just get a stable population going in there! Good luck!

(It might also help to feed your shrimp at night if you don’t already. So the smaller ones have a chance to get to the food while fish are sleeping.)