multiple Fresh water fish dead

[bigdscobra]

I recently did a water change on me fresh water tank... It is only a 10g tank... have a few different fish in there all small.. This morning they were fine. Just know I found 2 kuhlii loaches dead and my pelco died all have been in the tank for over a year.. One other kuhlii loache was swimming straight up than falling down to the bottom most of the time they stay at the bottom of the tank. Any suggestions????

[MikeDeL]

You didnt forget to declorinate the water did you? Sorry couldnt think of anything else from the info given, but sometimes we make stupid mistakes and over look them. How much water did you change? How does the water test?

[bigdscobra]

I used RODI water 50%

Another fish dead.............

Iam going to do a 50% water change right now...
their stomachs look red..

Dont know whats happing never had this before..

[alton]

Remember RO only takes out 2PPM of chlorine and has a difficult time with chloromines. I was having problems a couple of years ago because the local water supply company was pumping out 4PPM Chlorine and since have switched to chloramine, which is worse. Most chlorine drops will not remove chloramines. Also you need to add trace minerals back to DI water because you need those to sustain life. I found this out the hard way I killed my daughters turtle using only RO/DI water.

[Polkster13]

Carbon is the only effective way of removing chloramine. Do you have a filter that has carbon in it on this tank. If not, add carbon immediately. If you do have something in the tank that is poisoning the fish, this should help if it is not too late already.

[mathias]

sounds like something might of been added to the water because I doubt this the first time you did a water change?????

[Thunderkat]

If you waited a long time to do water change then wastes could have built up and killed them as they are senistive to that. Plecos are also very sensitive to salinity, if it gets too high they die. If you waited too long and evaporation raised your salinity then that could be it.

Did you add any new rocks or ornaments to the tank?

No idea about the loaches as I never owned those.

Do you have kids? They are notorious for putting things in the tank that could kill the fish like soap.

[Polkster13]

How can salinty be raised in a freshwater tank due to evaporation when there was no salt in there to begin with?

Plecos are notoriously hard to kill. They will live in just about anything, including no water. I had one jump out of a tank and when I found him he was completely dry and hard as a rock. I threw him back into the tank because I didn't want to deal with it at the moment. Came back a couple of hours later to dispose of him properly and he was swimming around like nothing had happened. Plecos are also caught in the San Antonio river where there is large amounts of pollution.

Since there was a mass die-off of bery hearty fish (loaches can tolerate even worse conditions than a pleco) and the fish are acting strangely, I would suspect that they had been poisioned by something that was accidently added to the tank. Running carbon in a filter will absorb most, if not all, of these toxins.

Adding new things to a tank could have certainly added something bad to a tank. Especially if you picked it up out of your back yard. But I am still convinenced it probably came from the water source. Have your RO/DI water checked and see if it has any chlorine or chloramine in it.

When was the last time you changed the filters? Do you have one or two carbon filters?

[Thunderkat]

How can salinty be raised in a freshwater tank due to evaporation when there was no salt in there to begin with?



Salinity can come about if you don't use RO water all the time, when I was a kid I used tap water and the dechloriniation stuff, I left for a few days and my water level was very low and all my fish were ok except my plecostomus.

Pleco = Plecostomus?

[bigdscobra]

Last night I did 50% water change using regualr tap water and did use dechlorifer.... Every thing seems to be fine haven't lost any more fish... The filter on the tank is the bio wheel 125 uses carbon in its filters... Also the RODI unit has a carbon filter too. The RoDI is brand new only used for the last month and have been used on my salt water tanks with no problems,so I guess it is a mystery why these fish died. The only thing that Ican think of is that one fish may have got sick and the others ate it... Hopefully their won't be anymore probblems ...

Thanks for your help

Dan

[gjuarez]

did you aerate your water?

[Polkster13]

Well Plecos are vegetarian. They will eat wood matter as well. It is good thing to keep some wood in the tank for them to munch on and they will usually be found napping there as well. To kill a pleco, it either starved to death or there was a bad chemical in the water that it absorbed. Because of the osmosis effects of fresh water, freshwater fish get water logged and have to pee to reduce the excess water in their system. They only "drink" water when they are eating. That is why freshwater fish can survive in very unclean water. However they do absorb a lot of things through their skins like heavy metals.

That is why I was concerned about the carbon filtration on your system. If your RO unit only has one carbon filter and you have chloramines in your water system that may not be enough. You might want to think about adding another carbon canister to your system. Also, how often do you change the carbon in your biowheel filter? Depending on the size of the tank, you may need to replace this a little more often.

Loaches are also pretty hearty. I am suspecting that the pleco died first, probably from starvation and polluted the tank. The loaches probably scavenged the pleco. If the tank were undersized for the amount of inhabitants (plecos should not be kept in ANYTHING smaller than a 50 gallon aquarium), the tank would have gone south on you very quickly creating a domino effect. If you need something to eat algae in your aquarium then I would suggest you look at otoclincus catfish. They stay small (1 to 1.5 inches) and like to be kept in groups of 4 or more.

[Polkster13]

Pleco is a generic term for many types of fish that resemble the plecostomus. What you commonly find in the fish stores is Liposarcus multuradiatus which will grow to about 2 feet long. Some "plecos" are omnivores and some are true carnivores. What most fish stores sell are herbivores to people so they can "control" their algae in their tanks. What they don't understand is that you have to feed these fish suppliments as the algae in the tank will not keep them alive for long. They do NOT eat other fish waste and they should not be considered "cleaner" fish. They need huge amounts of food fiber to survive, hence putting in the wood for them to munch on. They do make an attractive addition but they are not secondary fish. You have to meet their dietary needs or they will starve to death.

[bigdscobra]

I dont think he starved to death... He was always eating it must have been something with that water change.. I did another change with no RO water and havent had a problem since.. The pelco was only 2in long had him for over a year so he was still ok in that tank. I think it might of been that i never used RO water on the freshwater tank, i got the unit for my saltwater tanks and thats what it has been used for with no problems... I have had this tank for years and never had a problem like this with 4 fish dieing.. I got a new pelco today, the remaing fish seem to be doing ok ... The RODI unit has 3 carbon filters on it.. I have never used dechlorfire with it since i got it because i thought that it took all that out. The food fiber for the tank comes from this large plant in the middle it takes up alot of the tank. the leaves that fall off the pelco usually eats... I dont know what plant it is just a potted one from petsmart which has been in the tank for over a year..

Thanks for everybodys help!!!!!!!!!!!!! It was just werid never had that problem before.. I have had that tank since we moved here over 16y ago so this was the first time anything like that has happened..

[Polkster13]

Oh. I think I may know what happened. If I am reading this correctly, you have always used tap water before for your freshwater tank, Then the last water change you used RO/DI water. Is that correct?

If so, then it was a pH shift that probably killed the fish. The tap water around here is around pH of 8 and the RO/DI water is around pH of 7. if you did a 50% watre change that would have been enough to burn the fishes gills and that would also explain their behaviour prior to death. If you have a pH test kit, test the pH of your tap water, your tank water and your RO/DI water. I think you may find your answers there.

Let us know what you find.

[TexasTodd]

Dan, if you have been using SA tap water on the tank thus far..........and I believe you have since I know you haven't had a ro/di unit long, and then did a fresh water change with RO/DI ...........

YOU COMPLETELY F'D THE PH MY FRIEND. RO/DI water can't even be run through copper pipes because it will eat them. Not that we'd run anything for the fish tank through copper, just let's you know what it's like.

When we add Kalk or synthetic sea salt to the ro/di it buffers these problems out.

Just use regular SA tapwater with delcor additive stuff on your freshwater tanks. Not a fun lesson.

Sorry about the loss.

TT

[LoneStar]

yeah thats what i heard too

[bigdscobra]

Dam thanks for the help Todd.. Dont think I will be adding anymore RODI water to that tank.... Got some new cool looking tetras though, have a orange stripe..

[bigdscobra]

yeah thats what i heard too

Thats cause you were there when Todd told me that :roll

[LoneStar]

no, thats what i heard on the internet before todd told us