piranha eggs

[pegasus]

Sad news indeed.

.....
lesson learned. if it aint broke, dont fix it!!

Not quite... still have to find out why? Could it be lack of oxygen ?

[Julie]

Redbelly:  where did you get the java from?  which tank?

p.s. they will be spawning again soon.

Julie

[redbelly]

I took some java moss that was in the back of my planted tank. i was thinking the parameters of the water would have been different and maybe that cause a problem.

i dunno about lack of oxygen. they do have a bubble filter in there so i would have thought that would have been ok. but hey i have no idea really..

next time i think i will add a little air stone in there i think just incase . and maybe a small aquaclear with a big sponge on the intake.

[Mettle]

Realistically a sponge filter or the sponge intake put over an AC-style power filter should be cleaned on a daily basis in a fry tank. Or at least, that's my opinion on it.

[pegasus]

Realistically a sponge filter or the sponge intake put over an AC-style power filter should be cleaned on a daily basis in a fry tank. Or at least, that's my opinion on it.

No, not until the flow coming out is just a dribble or is not enough to re-oxygenate the water enough for the bio load.

I made widow screen bags to replace the sponges on the intakes as soon as I feel the fry are strong enough to escape from the suction of the filter but still to small for the normal intakes.

Could it be lack of oxygen ?

From the picture I saw, you had a dense population of fast growing fry in that tank. By adding the java moss, you might of decrease the surface oxygen exchange to a critical level.... It's just a tough..

[Woody]

I place java moss in all my fry rearing tanks. It is good for them, small organisms to eat off.
With a small tank that densely populated you would need a real mature filter, I use bubble up covered with a nylon stocking.
With that many fry an airstone or two would be necessary also.
Sorry for this loss, but your fish will spawn again, and experminetation is the key.
Try dividing the fry into a number of tanks, or increase the daily water changes, up to 50% with aged dechlorinated water.
There is a theory out there, maybe some one can elaborate, but when the oxygen level goes down, and with the amount of waste all those fry produce, you will have ammonia spikes, and any amount of ammonia  0.1 will kill fry as they are very delicate.
Even with a mature filter, they can't handle the bioload.

Woody

[Julie]

I think what killed those fry is high nitrates.  The ammonia spike would have made the tank cloudy which i think rb would have noticed unless he went to bed for the night.  
I know the fry need a larger tank as they grow and they are dirty eaters; but with proper hygiene in this 10 gallon at this point it would work for now.

Julie

[Woody]

The exact concentration at which ammonia becomes toxic to fish varies among species, some are more tolerant than others, but fry of all species are easily damaged. Levels of .01 ppm are lethal to fish as it hinders the hemoglobin in their blood supply. And the majority of the test kits can't even register this level.
In addition, other factors like water temperature and chemistry play a significant role. For example, ammonia (NH3) continually changes to ammonium (NH4+) and vice versa, with the relative concentrations of each depending on the water's temperature and pH. Ammonia is extremely toxic; ammonium is relatively harmless. At higher temperatures and pH, more of the nitrogen is in the toxic ammonia form than at lower pH.
You have an ammonia spike when their is insufficient filtration, not enough cleaning, or daily large water changes to dilute the concentration.
After the ammonia spike you get a rise in nitrites, at this stage when the nitrifying bacteria bloom, and they double in volume every fifteen hours, will you see any cloudiness in the water.  Three to four days after the ammonia spike, and after the nitrite spike.
At this stage the nitrite spike is also very dangerous to fry.
The amount of waste fry produce, coupled with the amount of food  fed to them, results in periodic ammonia and nitrite spikes in already established aquariums due to bilogical overload. A cycle within a cycle.
I personally have lost a number of large spawns, 300 plus fry in smaller tanks, I use ten and fifteens, while spawns of 50 or so survive.

It's very touchy when dealing with large number of fry in a small aquarium.

[Julie]

I think RB's tank is relatively acidic so the ammonia would not be anymore toxic in this tank.
I think the filter efficiently processed the spike to nitrate.  He didn't have that many fry in that tank.
The fry couldn't tolerate the high nitrate level for very long; and there are some survivors.

Julie

[Woody]

With acidic water you're right. A drastic increase in nitrates.  
Nitrates are less toxic than ammonia and nitrites but will cause undo stress, which can lead to disease as well as death if not properly taken care for immediately.  High nitrate accumulations are more toxic when oxygen is low though. Nitrates can do damage to the fish's red blood cells and this in turn causes them to be oxygen deprived. IMO that's why most died off but some survived.
Increased water changes would alleviate this problem for the next time Redbelly's piranhia spawn, and possibly an airstone or two to up the oxygen levels.


Woody

[redbelly]

thanks for your input!
i think nest time i will split them into 2 10g's. i am gonna put some extra filters on my main tank now, so when then spawn next the filter will be ready. and i think i will also and some airstones to be sure i have all my bases covered.
its to bad, but your right they will spawn again soon.