Trouble with 55 gallon tank

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DarienMcLean

Aquarium Advice Newbie
Joined
Apr 20, 2025
Messages
5
Location
Austin, TX
Hello all, I'm having trouble with a 55 gallon goldfish tank I set up. 2 Orandas, 2 comets, 4 minnows (now 1), 1 clown pleco, 1 loach (haven't seen it in a month).

I just lost 3 minnows in 2 days and now the goldfish are huddling in the bottom corner of the tank.

I have an API freshwater master test kit that I have been using to monitor the water quality every other day for the 2 months I've had the tank set up.

I change 20% of the water usually weekly, sometimes miss a week. Filters changed monthly.

Ammonia has been consistently high, (1-2 ppm) since I set it up. Nitrite at 0. Nitrate at 0. pH at about 8. Chlorine at 0.

I use ammo-lock every 3 days to little effect. Bought a second 75 gallon topfin silent stream to try to get more biofilter power (no effect). Have 2 medium airstones supposedly enough for a 75 gallon tank. Bought a couple gravel substrate plants to help. I add a dose of quickstart and stress coat with every water change.

Starting about 2 weeks ago, the water got milky white cloudy. It didn't respond to water clarifier. So I stepped it up to a 50% water change.

Then it got really milky cloudy. Looked greenish tinted, so added some algae killer and water clarifier (no effect). Fish were looking listless (despite water readings staying the same and water smelling).

Did an 80% change and added algae control and the water was clear. For the first time, ammonia was lower (0.5 ppm) but 3 minnows just died after about 2 days and my goldfish are huddled on the bottom VERY listless, like they are about to die.

Not sure what I am doing wrong. Could use some advice and tips.
 

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For starters, Plecos and Goldfish do not make good tankmates as their water requirements are opposite each other. Also clown plecos need wood in their diet as it's the main part of their diet.
Now for the problem: At 2 months old, the tank has probably not cycled and that is a problem. You seem to be adding too many chemicals which may be interfering with the nitrifying microbes establishing a foothold in the tank. Cloudy water in uncycled tanks is normal. It's a bacterial bloom that clears itself out after about a week or so doing nothing is the best way of handling that. With your pH level that high, when you do a water change, the non toxic ammonium ( end result of Ammo Lock) converts back to toxic ammonia due to your pH being so high. Ammonia naturally becomes non toxic ammonium at pH levels under 7.0.
I can't say for sure that this is not a disease problem because you would need to post a much closer pic or video of the fish's full bodies to check for external diseases however, all signs point to a water issue over a disease. If ammonia is the problem, it most likely has burned the fish's gills and they are having a hard time getting enough oxygen. What I would do is the following: Assuming your replacement water ( I assume its tap water) has the same pH as your tank water, I would get a clean 5 gallon bucket and add 4 gallons of tap water treated only with the Ammonlock for 4 gallons of water and place one of the air stones in the bucket at a flow rate equal to the rate of the stone under the single rock/log in the picture and see if that perks up the fish after 24 hours. If it does, the problem is the tank water and you should do a 100% water change in the tank and restart the whole process of doing a fish in cycle without adding all the chemicals. If it doesn't, you should do a 100% water change, gravel vacuum and filter cleanouts and reset the tank and choose either a fish in or fishless cycling method and follow the directions for which you choose. I would also get fish more appropriate to your tank size than the goldfish. They will get much to big for your tank.
Here is the instructions for a fishless cycling:

Here are the instructions for a fish in cycling:

Hope this helps. (y)
 
A weekly 20% water change isn't enough in an uncycled aquarium. A weekly 20% water change isn't going to be enough when you are cycled either.

4 goldfish and a pleco in 55 gallons will probably need twice weekly 50% water changes once you are cycked, and you may need to be doing those 50% water changes daily until your cycle establishes, possibly twice daily. Do as many water changes as you need to keep ammonia + nitrite both below 0.25ppm.

From what I've read, you are adding water conditioner (stresscoat), ammolock and algae control. That's a lot of chemicals. That won't be helping.

To control ammonia change water much more frequently, don't rely on ammolock or any other ammonia locking products. All this does is lock the ammonia in a non toxic state for a day or 2 at most, after which the ammonia again becomes toxic.

At your pH, and a typical temperate water temperature, ammonia is going to be a problem at about 1ppm, but keep it much lower than that as a safeguard. And obviously your fish have been living in toxic levels of ammonia for a while now which will cause long term health issues and the only way to combat that is pristine water conditions.

I would change your water conditioner to something like Seachem Prime or API Aqua Essential. Both claim to have the same ammonia locking property as ammolock. In addition the aloe vera additive in stresscoat isn't always good for fish. It coats gills and makes them less able to extract O2 from the water. Aloe vera also depolymerises in the water, and can cause cloudiness. I don't think in your case it is the cause of your cloudiness or issues, it's the high level of ammonia, but its something you can remove from the equation, and both those products I mention are better water conditioners than Stresscoat, and signifiantly cheaper too.
 
Thank you! This is exactly the kind of detailed advice I was hoping for and hope those steps help.

As a side note, you mentioned high pH being a problem (yes, it is that way out of the tap). Would it be any benefit to add some pH lowering products to the tank?
 
Adjusting pH chemically almost always causes more problems than it solves. It's much better to keep fish that suit the water than trying to alter water chemistry by adding chemicals.

As said above, you want to be limiting the amount of chemicals you use. All you need is a water conditioner for your water changes.

It's also going to be almost impossible to shift pH down. pH is caused by mineral content in the water, carbonate hardness (KH) in particular. KH is also called buffering because it absorbs acid, and stabilises pH. To lower pH you first need to overcome this buffering. These pH lowering products are mild acids, you add it and the KH just absorbs it and prevents it from working. So you add more. Then more, then more. If your pH is high, it's likely so is your KH, so you either have to add tons of these products to see any worthwhile effect or add a stronger acid. To lower pH you first need to lower KH, and the best way to lower KH is to dilute your high KH tap water with low KH water like distilled or RO. This means buying significant quantities of distilled or RO water for your water changes (you need a 50/50 mix with zero KH water to half the KH from your tap), or you buy an RO filter and make your own.

The high pH isn't the problem, it's the ammonia content. The pH just makes the ammonia more of a problem. Control the ammonia level to safe levels and pH doesn't come into it.

You are at the upper end of what pH your fish prefer, but i wouldn't look at adjusting things unless we think its causing problems. Water quality is the issue here, not water hardness/ pH.
 
In an uncycled tank, you don't want low pH. The ideal pH range for the nitrifying microbes is between 7.3 and 8.0 so your water is in line for optimal microbe growth so I wouldn't change it. Also, as Aiken mentioned, chasing a pH will usually cause more harm than good so you are better off getting fish that require your water's parameters naturally rather than constantly needing to adjust the water to suit a particular specie. Also, with so many fish now being farmed, what you read online about a specie will pertain to wild caught fish but if you are getting farmed fish, most are raised in water similar to the masses vs wild parameters so that should always be your first question to where you are getting your fish from: " Is this fish wild caught or farmed?" (y)
 
Hello Darien...

This hobby is 100 percent about removing and replacing most of the tank water and doing so often enough to keep the dissolving waste material out of the tank. I've been keeping tropical fish with cool water fish for several years and it's not difficult. But, none will live very long if you don't follow an aggressive water change routine. Goldfish produce a lot of waste, so they need half their water changed every few days. A week is too long. Twice weekly is about right. Only use chemicals needed to detoxify the tap water. Other chemicals just mess up the water. Start getting back on track by removing and replacing a little more water every few days. Get to the point you change out half the water a couple of times a week. You don't need to make tank keeping complicated. It's not.

B
 
Thank you! This is exactly the kind of detailed advice I was hoping for and hope those steps help.

As a side note, you mentioned high pH being a problem (yes, it is that way out of the tap). Would it be any benefit to add some pH lowering products to the tank?
Hey there, it seems to me your tank isn’t cycled which may be causing your problems. It’s fine to dose beneficial bacteria but stop using PH stabilizers and stuff they don’t do much. I personally like seachem prime which is the same thing as stress coat basically but it keeps fish safe from ammonia and nitrites for 24 hours every time you dose, which helped me a lot during a fish in cycle. Now, let’s talk about your tank husbandry. It’s a good tank size, but I would go for natural decor which is much better for fish and can help them feel more secure. Go for a dark aqua soil, plant your tank, and use REAL pieces of driftwood or spider wood to create little hiding spots and something your pleco can munch on. Honestly, substrate isn’t a huge deal and there are plenty of plants that can survive in your gravel but I really suggest you change it to the aqua soil I mentioned. If you need help, look up simple aquascape for online and watch aquascaping stuff on YouTube. Also, be sure to research the fish you have, goldfish are cold water fish while plecos like warm tropical water and need to have wood in their diet. And what kind of loach do you have? If it’s a dojo loach(white/albino or brown, pretty large snake-like body) it likes it likes cold water and if it’s a kuhli loach(black and yellow striped with a small snake-like body) it likes warm water and a group of 5. Good luck!
 
A weekly 20% water change isn't enough in an uncycled aquarium. A weekly 20% water change isn't going to be enough when you are cycled either.

4 goldfish and a pleco in 55 gallons will probably need twice weekly 50% water changes once you are cycked, and you may need to be doing those 50% water changes daily until your cycle establishes, possibly twice daily. Do as many water changes as you need to keep ammonia + nitrite both below 0.25ppm.

From what I've read, you are adding water conditioner (stresscoat), ammolock and algae control. That's a lot of chemicals. That won't be helping.

To control ammonia change water much more frequently, don't rely on ammolock or any other ammonia locking products. All this does is lock the ammonia in a non toxic state for a day or 2 at most, after which the ammonia again becomes toxic.

At your pH, and a typical temperate water temperature, ammonia is going to be a problem at about 1ppm, but keep it much lower than that as a safeguard. And obviously your fish have been living in toxic levels of ammonia for a while now which will cause long term health issues and the only way to combat that is pristine water conditions.

I would change your water conditioner to something like Seachem Prime or API Aqua Essential. Both claim to have the same ammonia locking property as ammolock. In addition the aloe vera additive in stresscoat isn't always good for fish. It coats gills and makes them less able to extract O2 from the water. Aloe vera also depolymerises in the water, and can cause cloudiness. I don't think in your case it is the cause of your cloudiness or issues, it's the high level of ammonia, but its something you can remove from the equation, and both those products I mention are better water conditioners than Stresscoat, and signifiantly cheaper too

A weekly 20% water change isn't enough in an uncycled aquarium. A weekly 20% water change isn't going to be enough when you are cycled either.

4 goldfish and a pleco in 55 gallons will probably need twice weekly 50% water changes once you are cycked, and you may need to be doing those 50% water changes daily until your cycle establishes, possibly twice daily. Do as many water changes as you need to keep ammonia + nitrite both below 0.25ppm.

From what I've read, you are adding water conditioner (stresscoat), ammolock and algae control. That's a lot of chemicals. That won't be helping.

To control ammonia change water much more frequently, don't rely on ammolock or any other ammonia locking products. All this does is lock the ammonia in a non toxic state for a day or 2 at most, after which the ammonia again becomes toxic.

At your pH, and a typical temperate water temperature, ammonia is going to be a problem at about 1ppm, but keep it much lower than that as a safeguard. And obviously your fish have been living in toxic levels of ammonia for a while now which will cause long term health issues and the only way to combat that is pristine water conditions.

I would change your water conditioner to something like Seachem Prime or API Aqua Essential. Both claim to have the same ammonia locking property as ammolock. In addition the aloe vera additive in stresscoat isn't always good for fish. It coats gills and makes them less able to extract O2 from the water. Aloe vera also depolymerises in the water, and can cause cloudiness. I don't think in your case it is the cause of your cloudiness or issues, it's the high level of ammonia, but its something you can remove from the equation, and both those products I mention are better water conditioners than Stresscoat, and signifiantly cheaper too.
Aiken, I've been following your guide that Andy linked to for a fishless cycling. (Moved my fish temporarily to a small 5 gallon tank that I'm changing water for every other day and though 1 goldfish died shortly after transfer, the rest are doing great).

Problem though on cycling the 55 gallon. I followed all the prelimimary instructions but 1) water started off 0.5 ppm ammonia. 2) after conditioning, I added Tim's ammonia chloride to around 4 ppm and added api quickstart for my bacteria. It has been about 4 days with no change in Ammonia levels, nitrites or nitrates. I even added an extra dose of quickstart to no effect after the first 2. Any thoughts on why nothing seems to be happening? Is quickstart no good for starting bacteria? Is something killing my bacteria?
 
Cycling an aquarium typically takes a couple of months, 4 days is no time at all.

These bacteria in a bottle products usually do nothing at all except make you poorer. This is something most hobbyists have agreed on for some time, but I recently found a scientific study that had tested various products and the only products that they tested to have any benefit where the various fritz products and Tetra safestart to a lesser degree. Dr Tims One and Only is the same product as safestart made by a different company. If you arent going to use one of those I wouldn't waste your money, and even if used one of those I wouldn't do so with any expectation that they work, just hope. If your water parameters don't suit these products they won't do much, if these products haven't been transported and stored in temperature controlled environments anything live will just die off in the bottle before you make your purchase. Cycling an aquarium is a long term thing, expecting anything to happen in 4 days is unrealistic.

In my opinion your fish are better off in the larger aquarium. You have a choice over keeping them in an uncycled 55 gallon or an uncycled 5 gallon. It's going to be much easier to maintain safe water conditions in the larger volume off water. Ideally these fish need to be in a bigger aquarium than 55 gallons, but if 55 gallons is what we are working with do 100% water change to get rid of the ammonia and return the fish to the bigger aquarium. Do those daily water changes on the bigger tank. Your fish won't do well for however long it takes to cycle your 55 gallon living in a 5g aquarium.

It could be that long term your 55g aquarium and filtration is simply insufficient to cycle and support 5 large messy fish.
 
Thanks Aiken. I think I might have found part of the problem. My heater wasn't plugged in so it was our home's 72 degrees instead of the recommended 82 degrees.
 
Cycling an aquarium typically takes a couple of months, 4 days is no time at all.

These bacteria in a bottle products usually do nothing at all except make you poorer. This is something most hobbyists have agreed on for some time, but I recently found a scientific study that had tested various products and the only products that they tested to have any benefit where the various fritz products and Tetra safestart to a lesser degree. Dr Tims One and Only is the same product as safestart made by a different company. If you arent going to use one of those I wouldn't waste your money, and even if used one of those I wouldn't do so with any expectation that they work, just hope. If your water parameters don't suit these products they won't do much, if these products haven't been transported and stored in temperature controlled environments anything live will just die off in the bottle before you make your purchase. Cycling an aquarium is a long term thing, expecting anything to happen in 4 days is unrealistic.
Nice to have some scientific evidence to back up my results with Fritz products. ;) (y) But with that, you still need to be within those recommended parameters to get optimal microbe growth. Anything outside of those parameters will effect growth rate. As you explained, 4 days is not a realistic timeframe. The reality to all these products is that they are really nothing more than an inoculation, not an established community. Adding them definitely shortens the cycling time but does not eliminate it. To eliminate it, we'd need to know how many microbes are present, :blink: how much ammonia and nitrite they can convert how fast :blink: , and how much ammonia a tank's bioload is creating and you'd need to have the production be lower than the microbes capabilities and that is just outside the average hobbyist's abilities to know. :blink::blink: :facepalm:
 
Hello all, just wanted to share a helpful update. I bought the Fritz Turbostart Freshwater 700 and added a tripple dose to my filter box. Within 24 hours, my water went from 4 ppm ammonia, 0 ppm nitrite, 0 ppm nitrate, to 1 ppm ammonia, 2 ppm nirite, 5 ppm nitrate.

Finally, the bacteria are starting to cycle the ammonia for the first time in the 2 months I've had my aquarium. The Quickstart I used a couple months ago and and the start of this current attempt did nothing.

The Fritz stuff was expensive though.
 
Hello all, just wanted to share a helpful update. I bought the Fritz Turbostart Freshwater 700 and added a tripple dose to my filter box. Within 24 hours, my water went from 4 ppm ammonia, 0 ppm nitrite, 0 ppm nitrate, to 1 ppm ammonia, 2 ppm nirite, 5 ppm nitrate.

Finally, the bacteria are starting to cycle the ammonia for the first time in the 2 months I've had my aquarium. The Quickstart I used a couple months ago and and the start of this current attempt did nothing.

The Fritz stuff was expensive though.
That's because you used the Turbo vs the regular Fritzyme. According to FritzAuatics, Turbo 700 has 15 times the amount of microbes as the #7 so you should expect to pay close to 15 times the price of the #7. In the end, speed costs. ;)
Sadly, what you experienced with the Quickstart is a typical experience many people have with other brands of " bacteria in a bottle" products. At least now you are on your way. (y)
 
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