Shrimp Dying Phenomenon

[AquaPit]

Hi

I have read somewhere that shrimps have a survival instinct where they will die for the sake of the new generation (in this case shrimplets). Especially the males.

If I remembered correctly, they do so because they want the new generation to survive and if the adult Male shrimps die, the new generation will have a better chances of living and also get more access to the food share.

The past 8 days, I have noticed the sudden death of my healthy adult RCS. This coincide with the new arrival of shrimplets (I saw only 2 though!)

All plump and very red adults.. Most likely Males.

Total casualty so far, 7 or 8 RCS.

Water test(water change 20% once a week)
Am 0
Nit 0
Nitrate 20ppm(readings have been very consistent throughout, highest it went was just 30ppm)
(Test done once a week, one day before routine water change)

Tankmates
7 Neon Tetras
3 Guppy Endlers

Tank Size (Overstocked Tank)
1ft Cube (8US Gal)

And... The phenomenon doesn't stop there, I even have 5 Red Nose Shrimps (Pinocchio) and 3 of them mysteriously died!

And just earlier today, I found out that the remaining 2, one of them is pregnant! I saw eggs!

So, is it true shrimps sacrifice themselves for the sake of a new generation...?

Hmmm...

 

[betta fish]

I have never heard of this but it may happen, I have bred RCS before and had many they were in a big 100L tank but I never noticed any deaths so this may just be the tank is small and they are running out of food, do you feed them? I always feed the shrimp as otherwise the fish will eat all the food, they got algae pellets they also quite liked nori which is seaweed sheets weighed down with lead.
Also it is the females that are bright red and plump, the males are smaller and very light in colour, nearly transparent, maybe with a few streaks of red.

 

[Baccus]

I can not scientifcally prove that shrimp (and other fish) have the males die for the benefit of future generations, however I have first hand experienced male guppies dying off in winter while the pregnant females survive to drop their young when weather and condtions improve. This could of course also be due to males tending to be smaller than the females and therefore have less body mass to handle varying water temperatures.
Have you read the following link by any chance?
http/www.fishforums.net/index.php?/topic/438726-cherry-shrimp-dying/?hl=antechinus#entry3715929
 
If all your other water paramters are fine and there has not been huge flux in temperatures etc then I wouldn't really expect the adult shrimp to start dropping like flies just because some shrimplets where due. Unless it is because your tank is overstocked and that is putting added pressures on the shrimp. At one point I had cherry shrimp in a 20L tank just for a breeding project, they never really did thrive although the tank got all the same care as my other tanks and the shrimp got all the same foods as my other fish and shrimp. Nano tanks can be great for available space, but they can also be more demanding in water quality, when things go wrong they go wrong quickly and drastically.
 
It could also be that the shrimp died just because it was their time, you said that they where both well coloured fully grown adults. So I am guessing that they where of similar age perhaps even from the same brood batch if purchased at the same time. I have heard mentioned by other shrimp keepers that they noticed some of the largest best coloured shrimp looked their nicest just prior to death. So it could be an age related thing
 
The reason I suspect that you only saw two shrimplets (besides the fact that they are excellent hiders) is predation by the tetras and endlers.
 
As for the rednose shrimp (I believe because of where you are they would be Caridina gracilirostris), these will "breed" in fresh water tanks but the offspring wont survive as they have larval stages that require brackish condtions and certain food types which they wont find in an aquarium. There is an Australian Red Nose Shrimp that can breed in fresh water, but I think they are only found in Australia and I am not sure if they are readily exported. So the sudden deaths of the Rednose shrimp I would be also be inclined to put down to age. Red Nose shrimp also need a lot of algea in their diet, so with such a small tank and competition from fish and other shrimp your rednoses may have actually starved while seeming to be surrounded by food.
 
To try and ensure better shrimp health and survival as well as a readily eaten food source for the shrimp I would look at giving them dried Indian Almond leaves and fresh or dried Mulberry leaves, both leave the shrimp will love you for it.

 

[AquaPit]

I have never heard of this but it may happen, I have bred RCS before and had many they were in a big 100L tank but I never noticed any deaths so this may just be the tank is small and they are running out of food, do you feed them? I always feed the shrimp as otherwise the fish will eat all the food, they got algae pellets they also quite liked nori which is seaweed sheets weighed down with lead.
Also it is the females that are bright red and plump, the males are smaller and very light in colour, nearly transparent, maybe with a few streaks of red.

Hehe.. yes.. they all are well fed.. with a variety

I can not scientifcally prove that shrimp (and other fish) have the males die for the benefit of future generations, however I have first hand experienced male guppies dying off in winter while the pregnant females survive to drop their young when weather and condtions improve. This could of course also be due to males tending to be smaller than the females and therefore have less body mass to handle varying water temperatures.
Have you read the following link by any chance?
http/www.fishforums.net/index.php?/topic/438726-cherry-shrimp-dying/?hl=antechinus#entry3715929
 
If all your other water paramters are fine and there has not been huge flux in temperatures etc then I wouldn't really expect the adult shrimp to start dropping like flies just because some shrimplets where due. Unless it is because your tank is overstocked and that is putting added pressures on the shrimp. At one point I had cherry shrimp in a 20L tank just for a breeding project, they never really did thrive although the tank got all the same care as my other tanks and the shrimp got all the same foods as my other fish and shrimp. Nano tanks can be great for available space, but they can also be more demanding in water quality, when things go wrong they go wrong quickly and drastically.
 
It could also be that the shrimp died just because it was their time, you said that they where both well coloured fully grown adults. So I am guessing that they where of similar age perhaps even from the same brood batch if purchased at the same time. I have heard mentioned by other shrimp keepers that they noticed some of the largest best coloured shrimp looked their nicest just prior to death. So it could be an age related thing
 
The reason I suspect that you only saw two shrimplets (besides the fact that they are excellent hiders) is predation by the tetras and endlers.
 
As for the rednose shrimp (I believe because of where you are they would be Caridina gracilirostris), these will "breed" in fresh water tanks but the offspring wont survive as they have larval stages that require brackish condtions and certain food types which they wont find in an aquarium. There is an Australian Red Nose Shrimp that can breed in fresh water, but I think they are only found in Australia and I am not sure if they are readily exported. So the sudden deaths of the Rednose shrimp I would be also be inclined to put down to age. Red Nose shrimp also need a lot of algea in their diet, so with such a small tank and competition from fish and other shrimp your rednoses may have actually starved while seeming to be surrounded by food.
 
To try and ensure better shrimp health and survival as well as a readily eaten food source for the shrimp I would look at giving them dried Indian Almond leaves and fresh or dried Mulberry leaves, both leave the shrimp will love you for it.

Yup.. tks.. I fed them Mulberry leaves twice a week

 

[StevenF]

I have not seen evidence that shrimp acratic themselves for the young to survive. In my opinion there are other possible causes that are more likely.

1. Ammonia or nitrite. You didn't see this but it may have been a very short spike. The sudden appearance of new bioload might trigger a spike and kill new as well as old shrimp. Also the ammonia spike may have had nothing nothing to do with the shrimp. Since new shrimp are are very small and hard to see you probably wouldn't notice the dead shrimp lets. An established tank with plants can eliminate all traced of an ammonia spick in less than one day.

2. New growing shrimp will need nutrients to survive. Like plants they need certain macro and micro nutrients. shrimp get most of them from the food they eat. However some are absorbed from the water they live in. if one of these dozen or so nutrients is depleted too much shrimp will die. Small soft water tanks won't have a lot of these nutrients available and A sudden surge in plant growth or the growth of shrimp lets in soft water can deplete calcium and magnesium and iodine. If these levels are low shrimp will die.