Plecos keep dying

I put this thread here as Wikipedia says that bristlenose catfish and bristlenose plecos are the same things but I'm used to calling them by the first.

I used to have three bristlenose catfish in a 10-gallon tank (yes it's kinda tight but they're fine for around 1 1/2 months). I travelled outside my home country for six weeks and one of them had died.

A few weeks later, the other one died. Can anyone please give me some potential reasons why they just die off so quickly?

Here are a few reasons why I think it's possible:

• Underfeeding: I have green algae wafers, but most of the time they never seemed to discover it. I always sink them to a certain spot in the aquarium and they never seemed to be eating it.
  Some people say that wafers sticked to the glass are more likely to be discovered but I don't have some to test out
  
  
• Territorialism: there's one pleco that's extra "big" at around 1 1/2 inches. Yes, it's still small, but bigger than the two other deceased (both almost 1 inch).
• My neighbor didn't take care of the tank properly while I was away. I could see leftover Danios food on the substrate (they're tankmates) and there's a good amount of beard algae

Here are some photos of a dead one, hopefully, if it indicates any reason for death:

That's not a bristlenose, it's one of the hillstream loaches possibly Sewellia lineolata.

As you can see in that link, they need tanks at least 30 inches long, fast flowing well oxygenated water and lower temperatures than most tropical fish.


Do you know the ammonia and nitrite levels in the tank? If the neighbour over fed the tank the left over food would have decomposed and possibly cause an ammonia and/or nitrite spike.

I don't have an ammonia test strip. Nitrite's just about 0.5 mg/L. Still trying to make it go down.

Any suggestions of how can I do so? The local pet owner only mentioned doing more water changes.

The way to get ammonia and/or nitrite down is by doing water changes every time they read above zero. It is important to be able to test for ammonia - could you buy ammonia strips?
Both ammonia and nitrite poison fish which is why they need to be kept at zero.

You can also reduce the amount of food you feed. The less food they eat the less ammonia they make and the less nitrite that is made from that ammonia.

I am going to vacuum the gravel next time I do a water change i.e., one week later. I really couldn't do it right now since I just did a water change a few hours ago and I don't want to disturb them fish again (I really ain't good at vacuuming).

I already reduced the food but nitrite's still hovering at around 0.5 mg/L

Clean the gravel every time you do a water change if there is a chance of uneaten food and/or a lot of fish poop in there.
If nitrite is still more than zero after the water change, you really need to do another.
How much of the water do you usually change? When there are poisons in the water (nitrite) you need to remove almost all the water, leaving just enough so the fish are covered. Provided you add dechlorinator amd get the new water to the same temperature as the tank water, a water chnage is less stressful for the fish than living in water with nitrite (and possibly also ammonia) in it.

The second and third one for sure looks like a hillstream loach - I love them. Plecos and SOME catfish species are in the same family so the way Wikipedia writes it is that All pleco's are in the pleco family but only some species of catfish are in that family. Now you have plecos,, possibly catfish and a Hillstream loach. They are all really close relatives to each other. Now when I first got my Hillstream loaches I lost one immediately and another one about 6 months later. never did know why. But compared to my other fish I've always found my plecos to be really tough. Even the babies don't back down from some bigger fish they are so cute., like a bunch of yellow tanks (all mine are albino or yellow and one is starting to turn brown). I have never had a natural death of a pleco. But over the 4 yrs I've kept them I have twice had some strange "accident" with my tank water and lost a number of fish including all my plecos and loaches. I have an assistant that does the water changes and the one I had at the time was really careful but each time we lost about 15-20 fish in a tank - it would just break our hearts. I'm assumming either the PH was too high (I have an additive that has to go in the water before you put fish in, and it lowers the PH to exactly 7.0 - otherwise the fish would be hit with a ph of 9.4 OR she forgot to condition the water to remove all the clorine and cloramines, We use Prime so it would also lower the ammonia and nitrates - so I'm betting that's what she forgot - they just all dropped dead at the same time it was like a horror movie

I would do a water change first of all to fix any mistakes your friend made, then get some algae wafers. I kind of soak mine in the water first and then break them into pieces, especially for the smaller pleco/loach/catfish. Once a tiny little yellow pleco caught an entire disk of algae and he swam (sort of) over to it and covered it with his entire body - he was not going to let anybody else eat his algae! I was so cute. But right now mine look about the same size as yours do - which is about 1/2 grown so I soften the algae disk and break it into 4 pieces, A lot less waste too. But I don't think any of mine have ever starved to death as far as I know. Now Hillstream loaches really like fast flows of water - so make sure you have an air bubbler so they can sit in that stream of water. There are also wavemakers for your water but that again would be for your Hillstreams. But you know I have noticed some Plecos either wrapped around my heater or wrapped around an airstone/bubbler, So check water termperature and make sure you have highly oxygenated water. So many plecos, catfish and loaches hide so they may need more air.

And so sorry you lost these, they look beautiful. Doesn't look like there is anything wrong with them so I guess assume they weren't being fed properly.

Jan Cavalieri said:

...Doesn't look like there is anything wrong with them so I guess assume they weren't being fed properly.

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Or perhaps the water parameters were never managed, leading to at least excess nitrites and indicating poor tank management.

With a shoal of danios and hillstream loaches in 10 gallons, the tank would need a lot of maintenance - large weekly water chnages and possibly more than once a week.


A few more questions -
Were all three "bristlenoses" the same species of fish? Bristlenoses and hillstream loaches are not closely related, just both eat algae but have different needs.
[bristlenoses are plecs, hilstream loaches are loaches]

Does the tank have a filter? What type, and what is the media? how often do you clean the media, or do you replace it?

@Essjay @Bruce Leyland-Jones @Jan Cavalieri
I apologize for the late/long reply but I was shortly unavailable

How much of the water do you usually change?

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Around 50% per week

When there are poisons in the water (nitrite) you need to remove almost all the water, leaving just enough so the fish are covered.

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I've done it once and those danios tried to jump out the next day (one actually did so I'm kinda traumatized while doing that). I'll test it out if vacuuming the gravel doesn't do anything. Just curious, could this have led to swim bladder disease?

Provided you add dechlorinator amd get the new water to the same temperature as the tank water

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I add the amount of Seachem Prime according to the packaging. The temperature of the new water should be within a difference of 1 degrees celsius.

Or perhaps the water parameters were never managed

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Yeah, I was away for six weeks, my neighbor ofc couldn't learn all the things at once. Honestly though:

I'm pretty sure I've hit all of these except that the temperature usually hovers around 79 degrees F. I couldn't really manage that since I'm living in a tropical region on the higher floors of an apartment next to a window. It will take a few days for my broken aquarium fans to return, though I doubt they're going to contribute much.
gH=60 mg/L, kH=40 mg/L. Not quite sure how hard is that but it should be on the softer side.

I'm assumming either the PH was too high

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Weirdly enough, my tap water is quite acidic... counting in around 6.0 or so. I bought alkaline water that can raise the pH to 6.5 or so but I'm not sure if it's the correct way of handling pH changes. My local pet store has no products to deal with that kind of problem.

Doesn't look like there is anything wrong with them so I guess assume they weren't being fed properly.

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That's the point and a problem I've been struggling with for months. Back when I had a smaller tank, they could easily find the algae wafer. Now with the new one with plenty of plants, they never seemed to find them...
I'd be really grateful if anyone can share how do they get their plecos/loaches to eat their algae wafers. I heard that there are ones that stick to glasses but I'm not sure how they will work out. Could it be that the food that I use doesn't appeal to them (this one)?

Were all three "bristlenoses" the same species of fish

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Yes. What bugs me is that the pet owner keeps like seven of those in a 4.5-gallon tank but they seemed to be doing fine.

What type, and what is the media?

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They're just regular ones with activated carbon, some filtering media (like some cotton-like but not exactly material), and a pump. There's a big and a small one:

• The big one: around 24 gallons per hour. Seachem seagel (link) with ceramic rings. Replaced once every three weeks
• The small one: 5 gallons per hour. Regular activated carbon with nothing extra. Replaced once every two weeks

I know it's just half of the recommended volume * 6 gph formula, but I'm not sure if that's overkill.

You don't need the carbon in your second filter, I would replace it with either ceramic Media or a sponge so that it encourages bacteria to grow on it. 10 gallon tank is really too small for danios and as someone mentioned the hillstream loach needs current and colder water I know you said you were waiting for your fans to come back or to be repaired but you should really try to lower that water temperature for it. And as someone mentioned when you have any ammonia or nitrites in a tank with fish you need to do a large water change to get as much of that out of the water as possible because it will kill your fish. Also while you were away your neighbor probably could have fed the fish once a week and it would have been enough for the fish, fish don't need to eat everyday.

A ten gallon tank is incredibly small for all of that. You absolutely need to know at least the most important water chemistries Ammonia, Nitrites, Nitrate and pH gH. It doesn't sound like you have all that you need to do so. I would go get the API freshwater master test kit.
Get a good water conditioner that also neutralizes Ammonia and the Nitrites. It sounds like your fish were being slowly poisoned from the waste. (Excess fish food and biological overload on tank size.)
Do daily large water changes until all Ammonia and Nitrites are gone.
Make sure you have a good filter for the tank. Maintain it well and frequently.
Once all of these are fixed you won't have a problem getting the fish to eat their food. Hillstream loaches want more than just algae wafers though. They will also clean up uneaten food. It sounds like all of the fish have been overfeed for awhile. Like others have said get in there with the gravel vac and really get as much fish poop and food out as possible.
Get some good beneficial bacteria to make sure your tank is fully cycled.
Good luck let us know.

crimsonpython24 said:

Around 50% per week.
I've done it once and those danios tried to jump out the next day (one actually did so I'm kinda traumatized while doing that). I'll test it out if vacuuming the gravel doesn't do anything. Just curious, could this have led to swim bladder disease?

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When you have poorly fish, more regular water changes are usually necessary. You problem is that you haven't a clue as to what 'water parameters' are, so you're not yet able to test for them and seem to be depending on guesswork and a 'pet owner' who hasn't advised you correctly.

crimsonpython24 said:

View attachment 141530
gH=60 mg/L, kH=40 mg/L. Not quite sure how hard is that but it should be on the softer side.

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What you really need to be testing for is ammonia, nitrites and nitrates. The first two should be consistently zero and nitrates less than 25ppm, (though upto 50ppm might be tolerable, depending upon your fish and tank set-up.

crimsonpython24 said:

I'd be really grateful if anyone can share how do they get their plecos/loaches to eat their algae wafers.

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Please lose the idea that these are 'plecos'. They are not. They are, as has been said before, hillstream loaches and have a very specific set of requirements. (Look here). I'll put good money on these being sold to you as algae eaters, to manage your algae.

Is there anything in either of the filters that you don't change regularly? Changing filter media means you throw away the good bacteria which have grown. The best types of media are ceramic and sponges as they don't need replacing until they fall apart after several years. They just need to washed in water that you take out during a water change.

GH at 60 mg/l is the same as 60 ppm and 3.4 dH. It is soft water.

This is going to sound mean, I don't mean it to. How did you think these are Plecos? They are very, very different. Did someone tell you that these are plecos? If so don't take any advice from them. Please get a much bigger tank, even if just for the danios.. They are really active and need the space. That also could be a part of the reason they were jumping.