Tank Cycling

Hello Venus,

I’m goldfish sitting again. This time, just for 12 days. Since the pump and pond sponge was added last time, it appears that good bacteria were able to grow in the tank!

This is a 5.5 gallon tank with 3 small fantails. Unfortunately, I will not be able to upgrade the tank size as it is not my tank 🙁

Current readings are:
Ammonia=0, Nitrite=0.5, Nitrate=5, pH=7, KH=0.
(No GH reading until new tester arrives).

One of the fantails’ tail frayed before and apparently the tank was salted. When the tail healed, it became black. Current salinity is 0.03ppm. One side of the black tail is longer than the other. I’m not sure if it’s completely healed but I imagine this happened as a result of cycling. The top fin of that fish is also slightly torn. Should we add any treatment to assist in the fin/tail healing? Or is fixing water parameters enough?

Do you think we are in the middle or tail end of cycling this tank? With the current nitrite and nitrate levels, how often should I be doing water changes and how much water should I be changing? Should I dose Prime for the amount of new water added or the entire 5 gallon tank?

Since the KH=0 (very low mineral quality), should I add some backing soda? Our tap water also has close to no minerals and low pH. I have already ordered some small wonder shells to arrive next week. In the meantime, should I add baking soda to raise KH and then add the shells to maintain KH? Or just wait for the shells and rely completely on the shells to raise and maintain KH/GH? If I add baking soda first, how much should I add for 5 gallons?


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  1. emme April 14, 2018 at 3:15 pm

    Hi Venus,
    I think the maximum time the fish will be in transport should be 1hour, likely less. My concern now is the Nitrate in the tank water used to transport them. You know I’m scarred from the last time. Will shallow tank water with Nitrate harm the fish? I noticed ammonia =0.1, Nitrite=0, Nitrate =10-20 so I’m cutting down on feeding and did another water change dosed with a full dose of Prime for the tank

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      Venus April 15, 2018 at 6:06 am

      These are real concerns, as fish that have suffered nitrate poisoning have no tolerance of shallow water. I wouldn’t cut down feeding, because your brother will feed normally, and this could cause a spike. Yes, the Prime will be helpful, as it will convert 10 ppm of nitrates per dose, or so they say. I would chill their tank water before the move, and this will doubly assure they feel no pain; 50 to 55f if possible. This way, if they were to have car trouble, it buys time. If you move them in an ice chest, the water stays cold for a few hours

      It will be hard to say goodbye?

  2. emme April 8, 2018 at 8:04 pm

    Hi Venus,
    Ammonia =0-0.1, Nitrite=0 and nitrate=5-10.
    KH=110, GH=160.

    I think it’s safe to say that the cycle is now complete?
    I am preparing to return the fish tank in the upcoming week.
    Now that the cycle is complete, how often should water changes be done? And how much water should be changed out? I am slowly transitioning back to feeding just flakes twice daily.

    When it comes to returning the fish, I had in mind to remove half of the tank water into a bucket and place the 2 fish into that bucket for transport. Then leaving the other half of the tank water in the tank with pump immersed for transport. When everything arrives at my brother’s girlfriend’s home, should they just fill the tank with treated fresh water? Or add the bucket water back in?
    What’s the best way to transport? Thanks!

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      Venus April 9, 2018 at 7:33 am

      How far will the fish have to travel? If an hour or less, a bucket is fine, but if the distance takes more than an hour, chill the tank water so they’ll use less oxygen. In this case I use an ice chest which keeps the water colder for longer

      Witht they cycle being so delicate, it would be wise to keep as much tank water as possible. If you can keep from adding more than 15% of freshwater that would be good

      Yes, I think the cycle is complete, but still delicate

      If you could transition your water changes to match the water changes you know they’ll perform, that would be great. If they’re willing to increase the number of water changes, instruct them on how you’ve been doing things. No matter, all changes in maintenance routine should be done very slowly. It all pertains, how much freshwater is added, how much waste water is removed and how much food is fed. Any change can result in a spike; nerve wracking isn’t it? A well established cycle can take a lot more than a new one

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    Venus April 2, 2018 at 5:40 am

    Yes, you can slow the water changes as the parameters improve. For example; if one day you have a reading of .5 ammonia, and you perform a water change using Prime, assume the ammonia is converted with a half dose of Prime. If the reading is the same the next day, there’s no reason to do a water change. On the other hand if the levels have increased next day, you would need to do water change and add appropriate amount of Prime

    If you know ammonia is rising though, increase amount of Prime to be on the safe side, but this probably isn’t the case

  4. emme April 2, 2018 at 12:42 am

    Hi Venus,

    Just an update on the tank cycling. I’m feeding twice daily (peas in the evening, flakes in the morning).
    Ammonia =0.1, nitrite=0.1, nitrate=5, KH=100, GH=180.
    Still doing water changes of 15%. I’ve reduced Prime dose to cover just the amount of water I’m adding because the parameters seem ok. Since the water parameters are consistently low, can I switch to water changes every other day? Perhaps the good bugs will grow faster this way?

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    Venus March 12, 2018 at 4:57 pm

    I emailed you, and yes, I regret not moving it to the tub, but SSG can result in the very same symptoms, and the fish would surely die if these gases were present, so you did the right thing. I’ve seen fish in the curled position for several weeks before treatment was offered that recovered. Every fish and every situation is different

    When a fish curls, it does so because the blood is thickening, and the body is constricting. It must be very painful. The fish should get relief in the deep water

    Should also warn you, once you add the Mean Green, you’ll need a flashlight to see the fish. You should be able to view it by pointing the flashlight on the side of the exgterior wall of the container

  6. emme March 12, 2018 at 3:40 pm

    So, the worst happened and the black-tail fish succumbed to nitrate poisoning.
    I found its body curled against the pump sponge today in the tank. I regret waiting last night and no taking it out of the tank sooner. I’m not sure how long it will survive now? It looked like it was having difficulty staying conscious and when it tried to move, its body was thrown with the water current from the pump and pushed toward items in the tank.
    I scooped the fish out of the tank and placed it into the deep chamber (20 gallons; 24″ deep) of water pre-treated with remedy from yesterday night. I also re-dosed with enough Prime for the whole 20gallons and hydrogen peroxide before placing the fish in. Before I left for work today, I noticed that the fish sank to the bottom of the chamber in its curled position but because it was too weak, its body also followed the water current and was pushed up and down in the chamber. Seeing the fish’s condition, I’m not too hopeful it will last more than a few days? How should I continue to treat this chamber tonight? Should I continue daily water changes? How much water should I change out/ replace?

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    Venus March 9, 2018 at 8:10 pm

    Consistency in water changes, sponge rinsing and feeding are the things that matter. If you’re going to change something, do so very gradually

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    Venus March 9, 2018 at 8:07 pm

    Are they all laying on the bottom, or just hovering above it, which is normal. Fish rest most of the night, and parts of the day. The older the fish, the more it rests.

    Okay. We might prepare for a spike after you increase feeding (slightly) and back off on water changes. I sell established pond pumps now and then. When I pull one from my tank, I feed a lot less, gradually working my way up. I’ve developed a feel for it, and never get a spike due to the fact. I think we all have this ability to feel our way through things, and although some parts of fish keeping are mater of fact; some aren’t

    If you damage the cycle? How will you know? There will be an ammonia or nitrite spike. As long as you’re getting zero for ammonia and nitrite with a healthy consistent reading of nitrates, the cycle is in tact

  9. emme March 9, 2018 at 1:17 pm

    Ok, I’ll back off on the h202 and water changes for now. I’ll feed small amounts of flakes again, yes. Though I really only started peas 2 days ago.
    I’ve used h202 for around 3days now. If I stop using it tonight and tomorrow and start your remedies on Sunday, will that be too much h202?
    I’m noticing that all 3 fish kind of bottom-sit/linger where the black-tail fish is in the morning. Is it because I am doing a lot of water changes? Hopefully I didn’t kill the cycle…

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    Venus March 9, 2018 at 6:30 am

    Conditions would have to be very good for some time in order for the fish to heal completely. The blood needs time to repair and rebuild itself, and this can only be accomplished in water rich in oxygen. IT could take months

    The max amount of H202 you could use safely is 15 mL three times a day, but I wouldn’t push it past three or four days. Also, keep in mind that when using my remedies, they contain H202. I’ll include in my instructions….coming soon. The remedy has arrived at its destination

    I think it would be wise to transfer the H202 to a spritzer bottle, and then mist the surface four or five times daily. You’re getting the KH up, and that’s going to assist the water in supporting oxygen on its own; very good. We’re keeping KH levels a little lower than I would normally recommend due to the fact the fish was burned by ammonia recently. KH also has the potential to burn fish, having the same effects, so until it’s tissue is completely healed, the lower KH is best. You’ve got a ways to go. In fact, let’s push it to 100 ppm. The condition of the blood probably takes priority over the condition of the external tissue

    You can back off on water changes now. The cycle looks to be complete. Although exchanging water reduces nitrates gradually, don’t knock yourself out. Looks like nitrates are at a safe level. Do you see any signs of algae? You might instruct your brother ‘not’ to remove algae as it builds on the glass, and it will soon if not already. There’s no plant that feeds as heavily on nitrates

    I once walked away from my stock tank for three weeks. No water changes were performed. The fish weren’t fed. The cycle was in tact, and the fish were just fine after the fact. They fed on algae, and algae fed on the nitrates

    Will your brother feed peas? I wonder if it’s time to change them over to the same food your brother will feed. Flakes? If there’s going to be a spike, best it happens on your watch. Feed flakes sparingly in the morning and just a few peas in the evening. In the wild fish feed constantly. They don’t have stomachs, and need food in their tract to encourage a healthy exchange of gas from intestines to swim bladder; the two being connected

    The fish is young; if the bloodstream is healthy, the organs will be soon to follow

  11. emme March 8, 2018 at 9:12 pm

    When I got home tonight, that fish was bottom sitting again. I’m thinking because the h202 wore off? I’m adding 10mL in the evening. Perhaps I should do 10mL twice daily? Morning and Evening? Is that too much for a 5gallon tank?

    • emme March 8, 2018 at 11:54 pm

      Ammonia=0, Nitrite=0, Nitrate=5
      KH=80, GH=200.

      Wondering if Nitrate shock can do permanent damage (e.g. to organs)? Do you think this fish will need daily water changes from now on? Or should it recover after the remedies?

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    Venus March 8, 2018 at 3:44 pm

    One thing I love about H202 is the fact it’s soluble in water, so the water doesn’t require a healthy KH (carbonate mineral) level. Still…this doesn’t mean we should depend on it. The quality of regular hydrogen peroxide purchased at a grocery store may be less than desirable. The Organic Fish’s Oop is oxygenated water with organic H202 as its base. It comes as 35% compared to the normal 3 or 7% found in the shops. Handle with caution

    I don’t know the maximum amount of H202 that could be used, because I’ve never pushed it to the limits. Since I didn’t no of anyone that ever used it, I had no idea how to judge the portions, so I crossed my fingers, and hoped for the best. It worked. It’s been four years now since I first started experimenting with it, and I feel pretty good with the results

    When it comes to remedies, over the years I’ve increased portions with some, and lessened with others, with salt and H202 being the latter; mainly because both are powerful. One reason I add H202 to the remedies is to give them longevity, but its true purpose is to give the herbs I use a boost. They’re useless when used in water low in value

    A few years back I read about a guy that maintained ponds. He used it for a pH crash, so knowing I wasn’t alone gave me a lot of confidence. I don’t want to kill a fish trying to save it. In most cases, less is more, and this especially true of H202

    Many a fish suffering from lockjaw has been saved the solution

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    Venus March 8, 2018 at 3:13 pm

    That’s great news. H202 saves the day.

  14. emme March 8, 2018 at 12:10 pm

    Somehow this morning, that fish pulled through! I do think it was the h2O2!
    I was beginning to lose hope in the water changes. Will continue tonight! And excited to get the remedies on Saturday 😀

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    Venus March 8, 2018 at 6:38 am

    The black marks indicate healing burns, not bacteria infection. It takes several weeks for fresh burns to turn black. It’s hard to say why some fish make it through a cycle without a mark, while the others show signs of stress. Toxins form in clouds, and this fish was unlucky enough to be hovering in the wrong place at the wrong time

    Don’t beat yourself up, as these injuries occurred many weeks ago. You’ve done everything possible to keep them healthy. This is sad to hear after everything you’ve done for them

    Fingers crossed it pulls through

  16. emme March 7, 2018 at 11:16 pm


    The black tail fish is very weak. It’s stuck to the gravel as low as possible far from the pump. When it moves it’s because the pump is too strong and pulling it toward the pump sometimes. It swims to stop itself from being sucked toward the pump. I turned the pump strength down to half so it can at least sit on the gravel. It seems to have developed some black marks on some of its body too. Burns?? When it swims, it kind of floats around aimlessly and its fins move it a bit. Meanwhile the other 2 fish are swimming with no problems and pecking at gravel. What can I do? 🙁

    Can we be sure it’s nitrate shock and not bacterial infection? (Black sores on body)

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    Venus March 7, 2018 at 6:51 am

    Feeding peas will help something, but probably won’t effect the condition caused by nitrate poisoning or shock. You’re not taking all the blame. I should have remembered the fish had a rocky past. Nitrates were pretty high when the fish arrived. It’s weird, because the fish can behave perfectly normal until a large water change is performed, and then it happens

    Maybe you can coach your brother on how to perform a proper water change

    KH could be a little higher. Shoot for 90 ppm. Heavily oxygenated water, that’s cold and deep is the cure for these fish that have been poisoned by nitrates and time, lots of time.

    I don’t think we can expect him to buffer KH, but he might spritz the water H202. Hydrogen peroxide comes in little spritzer bottles. I spritz the surface of my water daily, and someetimes more

  18. emme March 7, 2018 at 12:26 am

    Hi Venus,

    I measured ammonia=0.1, Nitrite=0, Nitrate=10-20, KH=70, GH=280 today.

    Now that you mention shallow water, it makes a lot of sense. I really do think that it was me taking the black tail fish out of the tank and placing it in the shallow tub that caused it to bottom-sit now 🙁
    Maybe even more so than the Nitrate levels which are not too high?

    The poor fish always swims lethargically now when not bottom-sitting. It seems to prefer to sit. It is still excited when the lights turn on or when food arrives. But otherwise slow and it looks like it has to put a lot of effort into swimming…. it almost looks painful? Will it get better over time?? I hope the shock does not become lethal!

    I changed out 30% of the water tonight, adding Prime, hydrogen peroxide and aloe to fresh water and split the water change into 5 parts so the water table was high at all times.

    Will feeding peas help anything??

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    Venus March 6, 2018 at 3:40 pm

    Lowering nitrates would help, but at the same time, the cycle is really delicate right now, and if you remove enough water to lower nitrates, it might spike. The Prime you’re using converts nitrates, so I say we stick to the water changing routine, but increase the dosage. Start with a full dosage today, double tomorrow, and then continue using a double dose every day.

    When you perform water changes, prepare the entire amount of freshwater you’re going to exchange, but instead of removing this amount from the tank, remove only two liters, and then replace with freshwater. Continue making this same exchange until the water change is complete. This is going to keep the water table as high as possible

    I think yes, the fish is sensitive to nitrates, and even though water changes aren’t to blame for the sensitivity, they definitely worsen the fish’s condition. Nitrates rob the blood of oxygen, and for some reason, the pressure of deep water relieves the pressure caused by nitrates. This is why fish sit on the bottom, in an effort to relieve the pain caused by pressure in the bloodstream

    Exchanging less water more often is the key, and can also prevent what I call, nitrate shock. Some fish that would otherwise be okay with a higher level of nitrates may experience pain when the water table is lowered

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