Tetra Canabalism?

[cornishgiant]

Hi,

In my tank (130L tall) which I have had running for a month now I have 8 black phantom tetras and 6 diamond tetras (and 1 oto (was 4)), all of which have grown quite big.

Yesterday, I bought 8 small cardinal tetras to complete my collection. I have dragged 2 corpses from the tank just now but can only see 2 live cardinals.

Is it possible that 4 dead/dying cardinals have been eaten by the other tetras?

I thought my tank would be ready now for cardinals, but obviously not yet. I tried feeding them this morning but they weren't intrested. Starved maybe?

 

[Tokis-Phoenix]

All fish are capable of cannibalism, even some of the so-called vegetarian ones, but your tetras are very small fish that dont have any bones and take very little time to rot awaycompletely- it can take as little as 24hrs for a dead tetra to disapear from rotting.
Do you have any test results for ammonia, nitrites and nitrates? How often do you do water changes(and how much, plus wether you add dechlorinator) and substrate cleaning sessions? The lack of eating is most likely down to discomfort, many fish will not eat properly when they feel ill. Cardinal tetras and otos can be very fragile fish and are difficult to acclimatise successfully to a new tank, and are not really really suited to reletavely new or cycling tanks.

 

[cornishgiant]

All fish are capable of cannibalism, even some of the so-called vegetarian ones, but your tetras are very small fish that dont have any bones and take very little time to rot awaycompletely- it can take as little as 24hrs for a dead tetra to disapear from rotting.
Do you have any test results for ammonia, nitrites and nitrates? How often do you do water changes(and how much, plus wether you add dechlorinator) and substrate cleaning sessions? The lack of eating is most likely down to discomfort, many fish will not eat properly when they feel ill. Cardinal tetras and otos can be very fragile fish and are difficult to acclimatise successfully to a new tank, and are not really really suited to reletavely new or cycling tanks.

Well, I tested the watrer, Ph7, Nitrite 0, Ammonia 0, Nitrates 15

Took a sample to the lfs where I got them, they told me that my ammonia was 0.5 (I am unsure of the units).

They seem to feel this is the problem.

I am sure they rot, but I have had 4 just dissapear! Where on earth have they gone?!

GForgot to say about cleaning, I cleaned out 40L the day I got the fish (lfs said mistake!) with hefty gravel cleaning since I had been away for a week and thought it was the best to do.

Normally I do 20L twice weekly.