Murdered Fish

[IanShorten]

It's almost certainly my fault that I scooped 37 fish out of my tank today. I've got a 31 gallon hexigonal tank and it had about 50 mollies given to me by a friend all juviniles. I live in a city with hardwater, and when I setup the tank I had them all living after a week and a half until today my first water change. I did a 50% as recommended by other sites for the first one. I'm assuming that this is what killed them and not my violent way of putting the water in. How can I avoid killing them in the future? The temperature was not the issue as I left the water in the bucket until I could check it was the same temp as the tank.

Currently I just have a dirt floor bed in it (Special fish shop dirt, not dirt dirt). Not sure if this effects anything or not.

Any advice or scolding is welcome.

 

[eaglesaquarium]

Did you dechlorinate the water before adding it? If not, you might have killed the biofilter, leading to ammonia poisoning and with that small a tank with so many fish, it probably wouldn't take long to build up to a lethal level, especially with the fish were weakened already from the nitrates that were building up.

Mollies like hard water, but the water chemistry may not be the same as what you added to the tank. Adding the water slowly allows the fish to slowly adapt to the changes in the water chemistry. A quick change in the water hardness could cause a problem as well. Most fish are actually quite adaptable to a wide range of pH, hardness, etc., but they need to have time to adapt to it before the change is complete.

For myself, I remove the water from my 56 gallon tank quickly, but I slowly trickle the water into the tank by a hose connected to my kitchen sink. It takes about 2-3 hours to replace the water in my tank after a 35% water change. My fish appreciate a bit of a temp change (I let the water from the sink come in much cooler than the tank temp, but leave the aquarium heater on - since its a fully submerged heater). My fish enjoy playing in the fresh water as it enters the tank. But, doing frequent water changes to keep the tank chemistry as close as possible to the tap water conditions is really the key, in addition to dechlorinating when adding water to the tank.


Any more information you can add will greatly help in determining the exact cause and help to stop repeating the same mistake.

 

[IanShorten]

Definitely didn't dechlorinate because I figured if they lived fine for a week then the water out of the tap was fine for them but obviously I was wrong. What is a biofilter? I haven't actually bought a filter yet, just have the pump at the top. I actually avoided doing the water changes because of some things I read about building the natural bacteria or something. I'll definitely change more often then in the future and try and add water back at a slower rate. I have a small suction thing I could use that might take an hour or so.

I guess my questions I still have are

1. How do I avoid poisoning them with amonia?
2. How do I avoid nitrate build up?
3. How do I declorinate?

I know I should have researched all this ahead of time but you know how it is, you just want to get started. Thanks for the help.

 

[eaglesaquarium]

I understand.

You are squarely in a fish-in cycle. Have a read through the link in my sig.

Really, you need to get yourself a glass of your favorite beverage, put some nice music on in the background, and have a read through the Beginners Resource Center. I could give you all this information, but no sense redoing what's already there.


To directly answer your questions though:

Biofilter - bacteria colony which "eats" ammonia and converts it to nitrite, another colony will "eat" the nitrite and convert it to nitrate. Generally, this colony lives in the filter for your tank in the media - floss, sponge, etc. This needs RINSING regularly to keep the water flowing, but needs to be replaced very INFREQUENTLY, once a year or so, even less. Some elements of the filter NEVER need to be replaced, as long as it is still intact.

1 - ammonia poisoning ultimately will be avoided once the biofilter is "cycled" (definition in the BRC). In the short term, water changes are the only way to be sure to keep the ammonia levels tolerable - that means large daily water changes to keep the ammonia levels at the trace levels.

2 - nitrate can really only be removed from the tank by regular maintenance water changes. Different folks have different routines. More populated tanks need a more rigorous schedule, either more frequent, or more sizable water changes.

3 - Dechlorinating is easy. Purchase a dechlorinating product like PRIME or STRESS COAT. These are easy to find in your local pet store. Just ask someone if you aren't sure. Prime is my preference because of its concentration - a little goes a long way - and it detoxifies ammonia to help protect your fish as well. It won't really affect your "cycle" either. It will just make life a little better for the fish. Stress Coat also detoxifies ammonia.


You are going to need to invest in 3 things immediately:
1 - a quality test kit for ammonia and nitrite. API sells a combo that includes pH, high pH, ammonia, nitrite and nitrate. The nitrate test is a bit troublesome, but it doesn't really matter... focus on ammonia and nitrite, and things will be fine. Then keep your water changes up.

2 - a quality dechlorinator. Like I said Prime is my preferred option. It may seem more expensive, but in the long run it isn't. On the contrary, its cheaper overall.

3 - Immediately, you need to buy a filter. The biofiltration will need somewhere to grow and the amount on the other surfaces in the tank is negligible compared to the filter. The filter has a high turn over rate of water moving through it, so the ammonia can't build up in different corners of the tank as stagnant water builds up. This is a necessity. Only fish that breathe some air regularly, like betas can get away with no filter, and even then, I still think that a filter (low flow rate) would be best for them.

 

[IanShorten]

Perfect. Thanks for the help. I just signed up today but I knew I needed to cause otherwise it's guess work for me which is never good for the fish. I'll certainly go read that introduction and other things available.

"1 - ammonia poisoning ultimately will be avoided once the biofilter is "cycled" (definition in the BRC). In the short term, water changes are the only way to be sure to keep the ammonia levels tolerable - that means large daily water changes to keep the ammonia levels at the trace levels."

Are you saying I should change it right now and see if those last few will live? What I still don't understand is why they wouldn't have a problem for a week but then all of a sudden amonia shows up and kills them all when I'm doing what's supposed to keep amonia levels low. I don't know. It's just not making sense to me. Anyways let me know what I should do in the short term to try and save the 10 left.

 

[techen]

Change water daily if you still have fish in that tank. Only way to keep them going. Water changes will keep ammonia levels down but to make bacteria on the filter will take weeks

 

[eaglesaquarium]

I suppose the information that's really needed as to why the mass death all of a sudden is where the tank came from in the first place, how long its been set-up prior to this week that you had it, etc. There are a lot of reasons. The exact cause of death is impossible to know without having more information. The idea right now is to get up to speed and do what needs to be done, in general. Unless we can pinpoint the exact cause of death, not doing a water change is actually worse than doing one in your situation. Since you have no filter, the tank has no way to deal with the ammonia building up. Temp match the water and dechlorinate before adding it to the tank.

I'd also suggest that you decrease feeding. You can't stop feeding altogether since they are juvies, but overfeeding would be horrible during a fish-in cycle. Feeding them only as much food as they can COMPLETELY eat in 15-30 seconds would be the amount to feed right now once a day, and I'd skip feeding once a week for now.


Read through the information in the resource center, and simply follow the guidelines given there. But, until you have dechlorinator, a filter and a test kit, you'll just be guessing and making a bigger mess. Its a bit of an investment, to be sure, but if you really want the fish to survive, you'll need them. Unlike other pet owners, the environment of our pets (fish) is completely up to the fishkeeper. There are no fresh breezes, warm spots in the house, etc. that the fish can go to to take refuge and get away from problems. They are at our mercy, and we need to make it right for them - to the best of our ability. Best wishes. The learning curve is steep, but in a month you'll be surprised at exactly how much you have learned and how rewarding a hobby it really is. (some would even say "obsession")