Normal mortality or something wrong?

[Annya]

Hello everyone,

I have a noobie question: what is a normal death rate (i.e. because of old age or other natural conditions) in a cherry tank? I'm asking because today morning I found a dead egg-carrying female on the bottom of my tank. The strange thing was that the front part of her body was very dark (dark-brown).

My tank has been inhabited for two months now. It is about 12.5 litre (about 2.7 gallons), inner filter with a sponge covering the inlet, with gravel, one piece of driftwood (from a good pet shop), one anubias, java moss and two other plant species (I don't recall the names now). No lead weights, no fertilisers added. Weakly 30% water change. It is inhabited by 7 adult cherries and probably around 10 baby shrimps now. Initially there were nine cherries, one died on the day of transfer to the tank two months ago.

I observed the other shrimps - everything seems OK. They show normal coloration, vigour and interest in food. Also the babies. However, I'm quite concerned about the reasons and if the other shrimps are safe. I don't want to buy more before I'm sure the ones I have can survive with me :)

In the last week I experimented with feeding them banana and boiled carrot (removed after 8 hrs). Maybe that is the reason?

[Jane of Upton]

Sometimes the shrimp can have parasites that you may not even be aware of. Was the body intact, or did it look like it had "broken". I had some wild caught shrimp in which several of the group died suddenly a few weeks after introducing them to an aquarium just for them. The top portion of the body, just behind the carapace, seemed ripped from the anterior portion. A fellow hobbyist said it sounded like a worm infection. It was very strange looking.

Death after transferring is not uncommon, as the transition of water conditions is very stressful. You might want to do smaller, more frequent water changes, as even 30% may be too much for them.

Did you peel the carrot before cooking it? Any vegetable that could have been grown using pesticides should be peeled to remove any residue. Bananas have a thick skin, so are generally regarded as "safe" once the skin is removed.

That's all I can think of for the moment.
-Jane

[silane]

Under non-optimal water condition egg-carrying female and young are first to go. Since you have a dead egg-carrying female, it is very likely that you water condition deteoriate, I will not look into things like copper or other form of toxic for a start. Just recall what is done for the past 3 days or what is not done for the past week as a routine.

Feeding them with vege/fruit has to be careful when your tank is small size. When my tank was small, whenever I feed vege, I have dead shrimps, and I feed with large amount. Now I am careful even with large tank, just feed very small amount of vege at one time and make sure free from pesticide.

[Annya]

Thanks for your answers.

During the last five days I spotted no more casualties in my tank. When doing a water change yesterday I saw what could be a dead baby shrimp, but it may as well be a baby molt (was so tiny that I cannot say).

The body I found was intact, only this dark-brown colour was strange. Before that death I followed the normal routine, only feeding banana and boiled carrot was something new.

The carrot was well-peeled before cooking (I removed about 2mm of the outer part), and the shrimps did not actually like it (only one seemed to take a bit, the others preferred looking for algae).

The only thing that has changed in their behaviour is that they are hiding more. For the last few days I never saw all 7 go out for feeding. Can it be because of molting? 3 of my females have just released babies and I saw 2 molts on the bottom. Maybe they do not go out so much until the exoskeleton is hard enough?

[GunmetalBlue]

Can it be because of molting? 3 of my females have just released babies and I saw 2 molts on the bottom. Maybe they do not go out so much until the exoskeleton is hard enough?

Hi Annya, very good observation. Yes, just before and after a molt, a shrimp won't be doing much of anything except hiding. I've seen a freshly molted shrimp before - where their body is literally collapsed on the ground because their legs are too weak to support them. As soon as they can, I'll see them get to a plant and hide for the rest of the day.

It sounds like you'll be having tons of growing shrimplets before you know it! If you didn't mind my making one suggestion - do you plan on continuing to breed RCS? If so, setting up another (possibly larger) tank for your growing population would be beneficial. It doesn't have to be anything fancy; say, a simple 10 gal tank will do. It'll be easier to keep up more stable water parameters too. Of course it's up to you; I bring it up now since you'd need time for it to cycle.

-GB

[Annya]

Thank you, that's a very good idea. Actually I'm going to set up a new, large tank for them, but I'll have to wait two or three months with that (It's possible I will be moving to a different town, not sure yet). Anyway, the numbers of shrimplets are still not astonishing (I can see only four or five from the oldest batch, they are two weeks old now, so they should be showing up these days, shouldn't they?). There are also some younger ones, but I can never see more than 10 at a time.

[Annya]

Unfortunately, I have just found another dead female. She was still carrying one egg with eye spots, so I think she died right after releasing her babies.
Now I'm really confused :huh: . Again, water conditions unchanged, no fertilisers, no CO2, 10% regular weekly water changes with conditioned water and no experiments with new food (only quality pellets). It has been over two weeks from the first death, so I don't know if it was related. Any ideas anyone?
I am really worried now, my population has shrunk to 4 females, 2 males and some babies. I wanted to get a stable breeding stock of these shrimps, and now they seem to be dying off. Four of them were bought as fully developed, large adults, so maybe it is old age. Still, 2 deaths over 2 weeks seems suspicious. :huh: :undecided . And I am really not neglecting this tank.