Is tank cycled or stuck?

[Lusoluv]

Hi all, I have a 40 gal breeder tank I set up 6 weeks ago and dosed with Prime and Stability. I was only semi-informed about the nitrogen cycle, and added 2 3" goldfish after 3 weeks, but before it was probably cycled. I lost 1 of them after 2 weeks and then started doing either 30% water changes every other day or dosed with Prime to keep ammonia and nitrites below 1ppm. 2nd goldie seems fine and active.

I saw a nitrites rise a couple times to ~2ppm a couple weeks ago, so did daily water changes to reduce. Now I've had 0 ammonia, .25-.50 ppm nitritess and 0-5ppm nitrates for about a week. The colors are so hard to discern sometimes. 7.6 pH has been steady.

I've read that I may not see the typical ammonia and nitrite spike/drop, and then nitrate spike as in fishless cycles. I have 2 HOB (400gph total), air strip and temp 72F. I feed my goldie 1 pea and 2 pellets twice a day. He wants more, but I don't want to create too much ammonia. I haven't done a water change since Fri and today is Monday. This is the longest the tank has gone without a change to the readings. Is there something I should be doing further? I feel my nitrates should have started rising? I stopped dosing with Stability since I don't feel it's done anything over the past month. Not sure how to tell when an unplanned fish-in tank has cycled or get a buddy for current goldie, but obviously happy my current resident seems healthy.

Any advice is greatly appreciated. I had tropicals and planted tank years ago, so not a total noob, but I've made some dumb mistakes this time!

 

[Aiken Drum]

You arent cycled, but not far off. Your ammonia to nitrite bacteria are removing all the ammonia your fish produces, but the nitrite to nitrate bacteria is only removing some nitrite. It must be removing some or the nitrite would be increasing, which it isnt.

I wouldnt worry too much about nitrate readings. You only have 1 smallish fish in 40 gallons and it probably isnt producing enough waste to create a lot of nitrate, your 5ppm nitrate since your water change feels about right.

Just give it a bit more time.

Note however there is no such thing as being cycled. You can be cycled sufficiently to remove all the waste your tank produces, but add more fish, more waste, your tanks cycle will need time to catch up.

I dont know what your plans are for stocking, but if the plan is to add more fish you arent far off that stage. See how things are in a week or so, introduce another fish, expect some elevation in your parameters, and control them through water changes as you have been doing.

Be aware that goldfish get big, and are very messy. Your tank is the minimum for a couple of goldfish and you should have filtration should be rated double the tank size.

 

[Lusoluv]

Thank you, Aiken Drum, for your prompt reply.

My HOB filter is a Marineland 200, rated for 30-50 gal tanks. I have 2 of them running since my research told me Goldies are very messy. I hope this is enough! I only plan on adding 1 more small fancy goldfish in the coming weeks. I don't plan to aggressively "grow them out". IOW, I'm not going to feed 4+ times a day, tons of bloodworms/protein, higher temps, etc. to get fast or massive growth.

Would this be a good plan: if I start feeding my current goldie a LITTLE more food, I'll see nitrates rise and generate a little more BB for a new fish in a week or two if parameters stay reasonable? Then when I add the new fish, I won't feed anything for a couple days so the new one can settle in and I won't add to the ammonia load too rapidly? Will monitor Amm and Nitrite levels daily and keep combined number below 1ppm.

 

[Aiken Drum]

Sounds good.

Ammonia toxicity is related to pH. At your pH i would ensure your ammonia doesnt exceed 1ppm. If ammonia is 0.5 and nitrite 0.5 thats going to be ok, but if ammonia gets up to 1ppm then do a water change even if nitrite is zero.

 

[Lusoluv]

Thank you so much!