Surviving a tank mini-cycle

[rosiedosie]

One of my fish tanks is majorly overstocked with cichlid fry but I thought my 3-times weekly 50% water changes would be enough to keep everything in shape. Last week I washed the filter in a bucket of tank water but it must have been enough to destroy all the good bacteria and now my tank is going through a dangerous new cycle.

I have had no light on this tank and the room light wasnt enough to properly show the fry. Last night I put a new bulb on the tank and was horrifies by what I saw. They all look like they have a few scales off around their heads and along their backs and about 5 of them are a sickly dark grey almost black colour (from what Ive read it is the healing of ammonia burn?) And the rings around all their eyes are a sad black.

WP then:

Ammonia: 2.0

Nitrite: 5.0

Nitrate: 80

Immediately after 90% water change and addition of a sponge filter from a cycled tank

Ammonia: 0

Nitrite: 0.5

Nitrate: 40-80

This morning

Ammonia: 0.25

Nitrite: 2.0

Nitrate: 10

Ive got no where else to put fry, no extra filters :( but they are looking much happier today. Im just about to do another water change, and I hope my fry are ok in the long term. I feel sick for makjng them go through that. Ive never let any of my tanks get that bad before, Ive never had a single fish get ammonia burn, I feel so guiltyn:(

[fishmosy]

Guess daily water changes is your only option, and you've done the right thing by adding the cycled sponge filter. Some of the commercial bacterial additives may help to cycle your tank quicker. And possibly an ammonia absorbing resin/filter mat if available.

My only suggestion would be to watch your feeding. Its unlikely that the fry will be eating as much as they were and any uneaten food equals ammonia. I'd even cut back feeding to less than once per day. Ammonia will kill your fry faster than starvation.

[Jess]

Maybe you could grab some Seachem Purigen (or equivalent) from your local LFS. This stuff is brilliant for removing ammonia and I keep a little bit in all my filters after the normal filter media to catch any excess nasties.

I can also recommend Seachem Stressguard as it neutralises ammonia (doesn't remove it) and therefore won't prevent your tank from cycling but will protect your fish.

Good luck!

[Daydream]

Apart from spong filter what other filter and filter media do you have.You could wrap dacron around your spong for extra area for bactria to live on.If you have other fully seeded filters clean the spong component directly in the tank going through minni cycle.This will add extra bacteria to seed culture in your filters better than anything you can get in a bottle. to As your filter is not copeing try to get as much surface area to cultivate bacteria on.

[BlueBolts]

Definitely need purigen or nitrazorb for the immediate removal of the Ammonia-Nitrate, with constant water changes etc.........Hi nitrates can cause continued deaths up to 3-4 weeks, so there's urgency to reduce these levels down ASAP. Hope all goes well....

[rosiedosie]

Thank you for everyones responce. I am using an 800ltr/hr canister and the tank is about 2 foot. Ive been doing twice daily water changes of about 70-80%. I ended up getting into a little disagreement with my partner last night because I wanted to pull the big fry out and put in the community tank just so that it will ease the pressure on the grow out.

Long story short, half of the fry are in another tank and luckily for me have NOT been eaten by the bigger fish (yet). But BlueBolts, I did notice a small fry stuck on the filter so I think the weaker ones are starting to shut down, like you said :(

With the grow out tank Ive slowed the water changes down to one daily of about 80% which is keeping everything at zero. How long will the fry take to heal? Theres a couple that are dark grey and two tiny little ones that are pretty much completely black :( :( they are happy enough and still eating, but dont look very good. I still feel like a b!*#h though :(

[BlueBolts]

2 x 70-80% WC is perhaps too drastic.....depends on the urgency, 25% should be ample, but 50% is perhaps OK. 80% is huge, and wouldn't recommended it, as such a sudden change of WP isn't good. Nitrates >20ppm is OK.

[Squiggle]

I agree with Bluebolts, 25% should be enough & I wouldn't feed the fry at all, they can last at least a week without any food. You need to get some zeolite into your canister, it removes ammonia, but then you have a catch twenty two of removing the ammonia which you need for the nitrate cycle. Prime is another product which when used in double or triple dose(up to 5x dose) can make ammonia & nitrite less harmful to fish as it bind it together into larger less harmful molecules, also Stability is a product which helps add beneficial bacteria while neutralizing harmful chemicals, hopefully this helps & you get through this. :encouragement:

[rosiedosie]

I do agree that they are very big water changes and usually I do no where near that much. But a few hours later the ammonia was creeping up again and getting over one. Nitrates were going back into the 40 range.

I have lowered the bioload on the tank by taking almost half and dumping them into the community tank, so the WC's were easing up as well. The remaining fry though, after I do the change they look like normal fry, after about an hour or so the rings around their eyes begin to turn black again. This is from stress isnt it?

So I should cut it back to about 25% water change? And starve them for a few days and see how that helps?

[rosiedosie]

Just a quick add-on, I have been adding prime to the water :) ♥ the stuff :)

[Squiggle]

The nitrates rising means that the aerobic bacteria is growing, you will just need time for the culture to grow large enough to handle the bio load. If you don't feed the fish then you shouldn't have a source of ammonia so it shouldn't rise after a day or two, hopefully by then your bacterial culture will catch up to the load. It is always much better to do lots of little water changes than one big water change, this way the culture will stay stable & not suffer from such a drastic change in conditions. I suggest doing a couple of water changes, morning & evening, & don't feed them until the ammonia level starts to stabilise & then a very small feed twice a day for a few days, then you can get back to what you normally feed your fish, weather that's once or twice a day :encouragement: