Feeding an oscar, then big problems....

[Bleeding]

This could also be a valid point. Acute poisoning. Or it could be the accumulative stress due to such gross overeating and metabolic disorder via poisoning, the synergictic effect of the two. Disease? No! Far too sudden. What also concerns me is the apparent hypoxia, evidenced by the respiration rate you witnessed, AND, you state if you don't do two 30% water changes per week your nitrate levels go through the roof, you lose a fish per day etc. Whilst it is great that you are doing two water changes per week, these should be seen ideally as a prophylactic measure, not a reactionary one.Your tank is far from overstocked, you are running an excellent canister filter yet your nitrates go through the roof. If these two water changes from the tap keep your nitrates under control then your water supply must be nitrate free. However, if you are not grossly overfeeding, are not overstocked and have a bio-muture filter thsi simply should not happen. Also most species have a high the toxicity threshold for nitrate, it is VERY, VERY unlikely nitrate could kill your fish short term. Ammonia and nitrite most definately, they would impair haemoglobin function within red blood cells. How often are you testing ammonia and nitrite? Have you cleaned your canister filter lately? If so how? Are you overfeeding? Has thee been any opportunity as tankyou suggested where your tank could have been tampered with? Filter turned off, something added to the water etc? Anwer all these questions and you may get to the root cause of your problem and be able to take corrective measures.

Well, i dont believe my tank is overstocked...especially since i just gave 15 of my fish to a monster fish....I test the water in my tank before each WC, at which time i test for ammonia, nitrite, and nitrate. And like i said, i DO notice that my nitrates are ALWAYS high (40+)...its hard to read on my test kit much higher than 40 because the water in the kit turns red and the shades of red on the color card are hard to tell apart....I just did a WC yesterday, and i just tested the water today...and my nitrates are STILL at 40???, its like the WC didnt help at all? This definatelly sounds like a reactionary system.

The other option would be overfeeding, but its hard for me to tell that either with so many little fish....I have a sand bottom, and it dosent appear to have that much stuff on it, other than feces....which i clean with the vac.

I also want to be clear that MY tank is the one in question now, which has not been contaminated (he DOES have a small child at his house who DOES put things in the tank, from soda to chocolate, but he was in bed at this time when this went down).....and the questions about my tank are, why do i lose fish periodically, why are my nitrate levels ALWAYS higher than normal, and why are my fish killing other species when eaten.

 

[Mentzer]

Firstly your water. Even though you state nitrates are 40+ ppm/mgl and it's difficult to quantify how much over (this is the case with most test kits, the gradations in shade are VERY similar and usually the same colour to make matters even worse) even say 50-60ppm is not a problem for most of the gamut fish species. Yes, perhaps discus, some catfish, marines, fry etc might not tolerate that level well but most species no problem. Secondly, due to both the frequency and volume of your water changes, and the fact the tank has a good sized external filter and is not overstocked there must be a problem with your tap water if nitrate levels are not falling. Do you test your tapwater for nitrate. (Check www.prcaticalfishkeeping.co.uk, register and look up the water change calculator section). Most people regrettably lose fish from time to time, there are so many variables involved, that's why we cannot get insurance for fish. Finally the small child was in bed, only you shall know the exact times involved, it's still not to say something was put in the tank. The timescales are still way too quick for disease, it just might have taken hours rather than minutes to manifest.

 

[Bleeding]

So....i just tested the tap water...............................not good:

Ammonia: 1.0 ppm (it may be between 1-2ppm but hard to tell with the shading)

Nitrite: 0 ppm

Nitrate: 20 ppm


Well this makes a little sense why EVERY time i test for nitrate, i have high levels.....if im putting 20 ppm in there each time i do a 30% water change......

Also, the PH is above 8 out of the tap.

So, am i putting toxic water into the tank? i know this level of ammonia, if nothing else, is unacceptable.....

 

[CHOMPERS]

That means your water is treated with chloramines. Ammonia is a funny thing. At a low pH it isn't very toxic but at higher pH's such as 8.0, it can be deadly. In the future, do not add tap water directly to your tank. Get a container that will hold the volume of the water change (plus some for top off). Pretreat the water for pH, Cl2, chloramines, and nitrates. Use Purigen or Prime (if prime will take care of the nitrates).

To make life easy in doing water changes with pretreated water, get a small sump pump and a garden hose. When the water is ready for use, add the pump and hose to pump it to your tank. (If your platty tank is still 20g, then this will be an over kill.)

 

[Bleeding]

Actually, the signature is not correct....my 20 and 30 are now empty, and the 55 gallon houses the platy, guppie, neon, dainos...

I havent made it to check out the calculator for water changes yet, but right now i have been doing 30%, which is around 15 gallons....this will be quite a bit of water just "sitting around"...are you saying to treat this water and let it sit between changes, or are you suggesting that i just treat it in a bucket, then pour it in?

 

[Zulu]

co2 poisoning. The added fish load sucked the oxygen out of the water, never recovered.

 

[Mentzer]

There you go then. The free ammonia levels at your pH would cause severe hypoxia due to haemoglobin damage within red blood cell platelets. The added load of all the feeders added simultaneously just tipped it over the edge. As Chompers has said you obviously need a 10 gallon water butt or small tank (24x12x15) the size of the volume you intend to replace with each change. On the basis of doing w/c twice per week (with good quality water) you could probably get by with 20% twice easily, probably even less, on the basis of low stocking levels and your filter. I would also get in touch with your local water authority and ask then for an explanation / comments regarding the ammonia. Register with the PFK site soon, lots of info there which shall be of help to you. Good luck.

 

[CHOMPERS]

...are you saying to treat this water and let it sit between changes, or are you suggesting that i just treat it in a bucket, then pour it in?

I treat my water and then pour it in. If you can find the space to let it sit, you can add plants to consume the ammonia and nitrates. Pothos vines are popular because they can be kept in water all the time, they thrive in low light and shade, and do an excellent job in consuming nitrates and ammonia.