Prawn Cocktail Anyone?

Canabalism in Freshwater Shrimps





Daragh

Firstly good choice of music. I had the sounds on load but didn't realise it. It just frightened the life out of me:laugh:

What type of shrimp are they doing the eating?
I noticed some of there own young going around. Are they eating a different type of shrimp or there own?

Oh! great vid by the way.

I got some snowball shrimp and some other shrimp described as "blue bees" about six months ago and kept them in a tank together. I am not sure what the blue bees actually are.

All went well at first and the snowballs were breeding like crazy, the blue guys eventually started breeding but the snowballs out numbered them about 3 to 1. Recently I have been very busy and just kept up with the water changes and feeding, but was not checking the population very well, when I did I was amazed to find that I had much more blue shrimp than snowballs, in fact there were only 11 snowballs in total, mostly very small and I think all male. There are at least 50 or 60 blue shrimp. I started to pay more attention to the tank and was amazed to find the blue guys eating the snowballs and others of their own species.

Advice on another invert forum suggested that the shrimp may be lacking in calcium and that's why they resorted to canabalism.



Daragh

Daragh_Owens wrote:

Advice on another invert forum suggested that the shrimp may be lacking in calcium and that's why they resorted to canabalism.

That's an interesting theory.

Now the thing to do to validate to some degree the theory is to check to see if after you discovered this is to see if any moulted skins are still in the Tank.

Kev.

Interesting stuff! They're voracious to say the least, mind your fingers Daragh

thanks for sharing another great video daragh. i also had a look through your other vids in the video section and they are an education. keep it up.

daragh, i was thinking that most of these shrimp are omnivore and will eat almost anything they are offered. but i doubt that they have the ability to actually kill something that is too big to swallow.
unless they catch other shrimp when shedding their shell and pinch them to death. anyway just a thought to keep the discussion going as i need to learn more about these little creatures and their behavior.

derek wrote:

daragh, i was thinking that most of these shrimp are omnivore and will eat almost anything they are offered. but i doubt that they have the ability to actually kill something that is too big to swallow.
unless they catch other shrimp when shedding their shell and pinch them to death. anyway just a thought to keep the discussion going as i need to learn more about these little creatures and their behavior.

I thought they were eating them alive from the looks of it Derek - overpowering them by force of numbers.

I have just spent nearly an hour replying in detail to these posts and get a message "to register" when I went to post.

Sorry guys but I am not writing that out again.

VERY pissed off.



Daragh

JohnH wrote:

That's interesting - so it doesn't only happen to us mere mortals

:o)

John

Unfortunately not!

When I posted this thread it was to demonstrate that dwarf shrimp are not the little angels we thought they were, well tonight I found out that Amanos have a nasty side too.

The pair of angelfish featured in a recent time-lapse video were a new pairing, never spawned before and they were initially great parents, but the day after they fry became free swimming the lost patience and ate the fry. Exactly two weeks later they spawned again, this time they got past the first few days of free swimming and the fry numbers had only reduced very marginally. The tank I used to spawn them contained 10 Amano shrimp which normally the angels pay no attention to, but when the eggs and fry arrived the Amanos were not allowed out of the flower pot they had adopted to hide in.

Last night I decided to remove the adult angels and raise the fry, I thought the parents had done a good job and the male seemed to be getting tired of minding the fry. Without the parents to herd the fry around in a big bunch the fry wandered all over and a good number hung around low down in the tank. The Amano took a day to realise they could come out of hiding and started mooching around the tank again. When I came home from work this evening, the fry numbers had dropped from about 250/300 to about 50. Each Amano had at least one angel fry in each claw and was deciding which to nibble on next. I tried to get some photos, but the tank is full of algae so none came out.

Moral of the story, never piss of an Amano!



Daragh

thats surprising all right. what size are the amano compared to crs or cherry.

I had ammano shrimp before and one of the guppy fry got too close and was snatched also,I intervened at the time but the guppy put up a good enough fight to manage to break free, they are opportunitic shrimp though.I cant get over how fast the numbers in the tank though went down from 250 to 50 in the course of a day given there are only 10 shrimp,surely it was a hunt rather a hunger requirement so then! They are rather quick shrimp also in terms of getting around the tank.

Gavin

Amano are about twice the body size of CRS or cherries.

In fairness I think hunger may have had a part to play, as I mentioned the angels had the Amano confined to barracks 24/7 for well over a week - but I drop in a tabimin for them every night.

The number is down to about 3 now. Sadly now that these Amano have "discovered" fry, I won't be able to use them in breeding tanks as cleaners like I used to, they have been "blooded".


Daragh