20 Gallon Tank Help! Cycling & dead fish

Heavyboom76

Member
Hey there .. I love this forum.. read it all the time and have got some great ideas and solutions to problems, but now I have one I can't figure out..

I recently bought a 20gl tank to take some fish from my overpopulated 50gl ..i cycled it for two weeks with that Stability stuff before adding fish. The ph was good nitrites were 0 nitrates were 5ppm, ammonia 0ppm temp was the same as my big tank..
I transfered a couple Molly's and a guppy.. did everything the same as I did with my big tank... The next morning they were all dead! ..and the water was super cloudy.

So I started over and this time cycled it for 4 weeks with Tetra Cycle I think its called... I took two fish from my big tank and the same thing happened they died over night and the water was super cloudy?

Has this happened to anyone? The levels of everything were spot on .. I did everything the same as with my 50gl the only difference was epoxy covered rocks and glofish ornaments..
 

Pfrozen

Member
Hi, you need to introduce an ammonia source during the cycling process. Otherwise the bottled bacteria just floats around and dies after a few days with nothing to eat. You can use liquid ammonia or perform a "fish in" cycle with a couple fish as long as you keep your combined ammonia and nitrite readings below 1ppm
 

Fisch

Member
So it sounds like you did not take media from your established tank?
Can you provide a bit more information and detail regarding your cycle attempts?
After adding the bacteria, what occurred at that time? How often did you add bacteria, how did you decide that the cycle was complete? What about Waterchanges?
What was your Ammonia Source during the cycle attempts, and I assume you had Ammonia levels during cycling?
Lots of questions...
 
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Heavyboom76

Member
I just thought it perplexing that i did everything the same as with my 50g tank .. I read on the stability bottle that you could add fish immediately as long as you kept adding the dose for 7 days ... in my 50g tank; after 4 days of stability I added about 10 guppies, adding molly', platy's, a pleco and some shrimp each week or so.. everyone is alive and well.. even the shrimp... the small tank has been killing everything.. we're starting from scratch again.. and this time we'll add the ammonia.. with the cycle.. for a month. The pic is the tank that doesn't kill everything.
 

Fisch

Member
every tank works different, the big tanks always seem to be more stable while the little ones are all over the place. It maybe the filter, the gravel, the decoration. The ratio is just different and the small water volume makes it less forgiving. I am with you, my first big tank did not have any issues, my little tanks took much longer to cycle and stay stable without frequent mini cycles.
 

Perlumia

Member
Personally, I've had luck using some filter media from my main tank in whatever tank I'm trying to prepare for fish.
 
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Heavyboom76

Member
Fisch said:
So it sounds like you did not take media from your established tank?
Can you provide a bit more information and detail regarding your cycle attempts?
After adding the bacteria, what occurred at that time? How often did you add bacteria, how did you decide that the cycle was complete? What about Waterchanges?
What was your Ammonia Source during the cycle attempts, and I assume you had Ammonia levels during cycling?
Lots of questions...
No, we didn't add any media from the big tank.. it has a Fluval Canister Filter and the 20g we bought was a complete kit.. with HOB filter. First time around we used Seachem Stability.. doses for 7 days and then it ran for like 2 weeks..added a few fish -DEAD.. Second round we used Nutrafin Cycle.. ran for 3 or 4 weeks after dosing, added a few fish -DEAD. the thing I thought was weird was how cloudy the water was within 8 hours of adding the fish, and a thick white sludge developed on everything.. I'm away at work right now, so my wife is doing it all but .. after the last fish died we left it running for the cloudiness to clear up and when she moved the gravel it clouded the whole tank immediately.. the gravel was FULL of the same white sludge that was covering the heater and thermometer.. We're starting from scratch again.. the guy at MarineLife told us to buy a scallop or shrimp from the grocery store and put that in while we're dosing with stability let it decay so the Ammonia spikes and then remove it and let the Stability do its thing.. this works
Oh also yeah.. before adding fish we tested the water and everything was good.. pH 7.0 Ammonia was 0 nitrites 0 , nitrates were like less than 5ppm..a week before the first fish were added a put couple pinches of food in to decay..
 

Fisch

Member
I am not familiar with HOB filters, but you may be able to get take some of the foam from your canister and stuff it into your HOB. IMHO Canisters have a bigger media surface, more spaces for bacteria to grow.
But starting over is a good plan.
I personally like the fish-flake or shrimp method, the trouble I have is the lack of control. Shrimp also maybe a bit risky as it stinks up the water and may foul.
My last tank I started with Ammonia to 2ppm, and then follow up with Fish Flakes to keep the level up. Just an idea, there are so many methods and everybody has their preference.
 
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Heavyboom76

Member
Thanks! I've learned SO much from the folks on this forum.. So with that, we're starting that 20gl with new everything and will be putting some foam from the canister in with the new filter..
 

mattgirl

Member
Heavyboom76 said:
Thanks! I've learned SO much from the folks on this forum.. So with that, we're starting that 20gl with new everything and will be putting some foam from the canister in with the new filter..
Starting over sounds like the best option in this case. Be sure you also clean every crack and crevice on the HOB filter. You don't want anything lurking in the tube. Also scrub the inside of the tank paying close attention to the corners and up under the rim.

You can add bottled bacteria and raw shrimp if you choose to do so but if I were doing this I would just add a few fish instead since you are going to be moving bacteria from your cycled tank. In my humble opinion that bacteria is going to be 100% better than anything you can get in a bottle.

If you are going to be moving fish from your cycled tank over to this one what I would do is do a water change on the tank they are in. Don't gravel vac or rinse filter media in the water you pull out. I would then put 10 gallons of this water in the 20 gallon tank and then top it off with fresh clean water. By doing this the fish you move over will just feel like they have just gotten a 50% water change.
 
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Heavyboom76

Member
mattgirl said:
Starting over sounds like the best option in this case. Be sure you also clean every crack and crevice on the HOB filter. You don't want anything lurking in the tube. Also scrub the inside of the tank paying close attention to the corners and up under the rim.

You can add bottled bacteria and raw shrimp if you choose to do so but if I were doing this I would just add a few fish instead since you are going to be moving bacteria from your cycled tank. In my humble opinion that bacteria is going to be 100% better than anything you can get in a bottle.

If you are going to be moving fish from your cycled tank over to this one what I would do is do a water change on the tank they are in. Don't gravel vac or rinse filter media in the water you pull out. I would then put 10 gallons of this water in the 20 gallon tank and then top it off with fresh clean water. By doing this the fish you move over will just feel klike they have just gotten a 50% water change.
Great advice! Thanks
 

Dechi

Member
What you did in the 55 gallons was not cycling, and neither was it done in the 20 gallons. Those bottled bacteria are mostly a marketing scheme. They don’t do much, except maybe give a little boost.

Lots of people don’t even use them. Cycling a tank means giving a way for beneficial bacteria that eats ammonia and nitrites to live and colonize by providing an ammonia source. This ammonia source can be in the form of rotting food or pure ammonia (fishless cycling) or fish poop (fish in cycling).

Either one of these two methods will take 4-6 weeks. In your case, you did a fish-in cycle in both your 55 gallons and 20 gallons. You probably did more water changes with the 55 or added less fish at once, which allowed your fish to survive.

But now you know better, so have fun cycling your tank ! :)
 

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