Please help my pleco

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blyatboy

Feeder Fish
Oct 20, 2025
2
0
1
35
Hong Kong
I humbly come to you all asking for help with my pleco.

Background

He is a L001 gold spotted Pleco around seven years of age, and up till recently, I kept him in a lightly planted tank, and fed wafers from Pleco Ceramics. I suspect he is stunted in growth since he spent his first couple of years in a very undersized tank before I rescued him. Besides his relatively small size, he is not deformed in any way. He shares a relatively overstocked tank with guppies.

Timeline

Thursday, 2nd of October: I first noticed that his mouth is "closed up" and he refused to eat. I left him alone, since this has happened before, perhaps 2 months ago, and resolved overnight.

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Saturday, 4th of October: His mouth was still folded in and he is very inactive. He was unable to "suck" onto any surfaces. I started to get worried at this point and took a much closer look. I noticed he did not exhibit heavy or exaggerated breathing. In fact, there was almost no visible movement in the gills, which is not normal for him. I noticed that every now and then (perhaps every 15 minutes or so) he will dart to the surface as if to take a gulp of air and then return to the bottom and remain relatively motionless. To me, this suggests that he is relying on these gulps for air, and not using his gills at all. At that point, I tested the water. The results showed zero ammonia and zero nitrate but high nitrates at above 80 PPM. I also got around to testing my tap water, which came out to around 20 PPM of nitrates. I immediately added an airstone, and performed a 50% water change

Sunday, 5th of October: Another 50% water change. During this water change, he finally managed to latch onto the glass, so I could shine a torch and take a look into his mouth. There was no visible obstruction, and his actual lips looked fine. While he was latched onto the glass, he was visibly using his gills, though the gill movement was quite weak.

Suspecting he might have hurt his mouth on the pea gravel, I removed most of it from the tank floor.

1st Recovery:
Monday, 6th of October: I still saw no improvement. With nitrates sitting at around 40 PPM, I performed a 25% water change, and turned off the lights to reduce stress. Right after lunch time, I was surprised to see that his mouth had opened back up. By around 6pm, I found him sucking on the glass and the floor again. Gills are visibly moving and he seemed to be breathing again, although it was a bit shallow. By evening time, he almost looked completely recovered, and seemed to be eating up the algae around the tank. Around this time, I remove the airstone, as I thought the two filters I have would provide adequate agitation. He was still fine by around 2 AM.

1st Relapse:
Tuesday, 7th of October: In the morning, I woke to see his mouth folded in again, and once again not visibly breathing through the gills. Nitrates were sitting between 20 and 40 PPM. I then performed a 25% water change. Similar to Sunday, he shifted around and latched onto the glass during this water change. He could not remain latched onto the glass, but I could observe that the redness I saw before was no longer there. I added in some new plants (a bunch of water lettuce and some driftwood with plants on them), and two Indian Almond leaves. Late afternoon, it hit me that the removal of the one airstone preceded the relapse in his previous behavior, so I added it in.

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Wednesday, 8th of October: In the morning, I performed a water test, with nitrates sitting just around 20 PPM. I performed a light 10% water change, and poured in some tannin water left over from preparing the Indian Almond leaves. No change in his mouth, still no visible gill movement, and he is still inactive, but still shifts around once in a while and reacts to surroundings or my movements. He surfaces for air around every 20 minutes.

2nd Recovery:
Thursday, 9th of October: In the morning, nitrates were sitting at around 20 PPM. I performed a light 10% water change. He was still mostly inactive, but I noticed his mouth would sometimes open up. Even when attached to the glass, gill movement seemed very minimal or unnoticeable. Just before lunch, I saw him begin to gingerly rasping on the glass, and after lunch time, he had begun eating some algae around the tank, and I even saw him rasp on the new driftwood I added for the first time. I notice his belly has noticeably flattened. I fed him a blanched cucumber and he ate it. At this point, I added yet another airstone.

Friday, 10th of October: Continued improvement. Fed a blanched cucumber at night and he ate it too

Saturday, 11th of October: No relapse. Ate a pleco wafer in the evening.

For the next week, he had been active, eating, and breathing normally. It was like a miracle recovery. I alternated between pleco wafer and blanched vegetable (either cucumber, pumpkin, or butternut squash). I will say that at times, the breathing seemed a bit fast, but I attributed that to activity.

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(going ham on a sponge filter)

Thursday, 16th of October: Nitrates were just above 20 PPM.

Friday evening, 17th of October, he enthusiastically ate a pleco wafer.

2nd Relapse:
One full week of recovery later, on Saturday the 18th of October, I noticed he was inactive again and seemingly unable to rasp/latch onto surfaces. I don't see much gill movement either and he seems to be going to the surface every ~20 minutes for air again. His mouth seems to have closed up again, although it does open up every now and then.

I tested for nitrates, and they were still way under 40 PPM, with ammonia and nitrite at 0 PPM. I performed the weekly 50% water change today, which was usually scheduled on Sunday.

I tried to feed him a blanched cucumber, and to my surprise, he happily ate it. After eating, his breathing seemed to resume a bit, and he grazed a little around the tank, although he was still quite sluggish.

Sunday, 19th of October: Still no improvement. I did a smaller 25% water change in the morning. I finally arranged for 50% of the guppies to be rehomed. I topped up the water lost from rehoming the guppies. He accepted a blanched zucchini, but after eating it, he was noticeably less active compared to last night. I also added a bit of tannin tea.

The Situation Now

It's now Monday where I am. I've turned off the lights again just to lower his stress. What I am noticing is after he goes to the surface and dives back down, he tends to dart around around for a bit, and it almost looks like he "coughs" a few times, before his mouth shrivels up again and he lies still.

I am totally lost now. Up to now, the guppies do not exhibit any signs of stress or illness, nor do I notice any discoloration or growths or any other symptoms not yet mentioned on my Pleco. Both air stones are still on full blast. He seemed to be doing so well for more than a week. What concerns and confuses me the most is this most recent sudden relapse.

So far, I have held off from medication, but I have Seachem's Kanaplex, Metroplex, and Focus on hand, along with PraziPro. I am weary of taking him out of the main tank because he is and has always been scared of people and environment changes, and I don't want to stress him out even more. Frankly, I'd rather take the remaining guppies and the nerite snail out. I am considering dosing his food, but he only seems to be accepting vegetables right now, and I am unsure about "shotgunning" meds without knowing what is going on exactly. That being said, I am no expert, so please help me out.

So, what do you think could be the problem, and more importantly, what should my next steps be? Is it time to medicate? Or continue to hold off?

Really appreciate it if you've read this far. I really wish love this guy and I had gotten him earlier, but now I really just want to give him the best care possible. I will do anything to help this guy get back on his feet.

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(during his 2nd recovery)
 
Hello; Reads like you have done some good things. I tend to agree to not "shotgun" medications without knowing the target. The problem may not be a pathogen.
The nitrate levels at times are a bit higher than most target for. Your approach to WC (water change) is one area that could be stepped up and will be mostly passive. Not suggesting the nitrates are causing the issue but larger volume & more frequent WC are a basic first step when a problem shows up.

Some often suggest adding salt to a tank but as i do not keep plecos I suggest waiting for suggestions from those with such experience.

Absent a specific clue about the only thing i can think of is the environment. I tend to run my tanks for many years before a tear down. I do aggressively siphon the detritus from the substrate during WC. I tend to have fewer decorations than in the past. again not suggesting the decor is the issue but removing much or all of it might wind up being a clue if the condition improves.

Afraid i am not being helpful. I do not have a good idea about the issue. Good luck.
 
Hello; Reads like you have done some good things. I tend to agree to not "shotgun" medications without knowing the target. The problem may not be a pathogen.
The nitrate levels at times are a bit higher than most target for. Your approach to WC (water change) is one area that could be stepped up and will be mostly passive. Not suggesting the nitrates are causing the issue but larger volume & more frequent WC are a basic first step when a problem shows up.

Some often suggest adding salt to a tank but as i do not keep plecos I suggest waiting for suggestions from those with such experience.

Absent a specific clue about the only thing i can think of is the environment. I tend to run my tanks for many years before a tear down. I do aggressively siphon the detritus from the substrate during WC. I tend to have fewer decorations than in the past. again not suggesting the decor is the issue but removing much or all of it might wind up being a clue if the condition improves.

Afraid i am not being helpful. I do not have a good idea about the issue. Good luck.

Thanks for your input, I appreciate it regardless.

I am leaning towards gill flukes actually. I hear many are species specific, and combined with their life cycle and my water changes, I think this diagnosis is the one that makes the most sense right now. But I'm all ears. Just feeling really lost right now.

If anyone else has any ideas, please do chime in. I'd really appreciate it.
 
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