Odessa Barb Attacked by BN Pleco?



What is the water volume of the tank? 75G
How long has the tank been running? 2 years
Does it have a filter? FX4
Does it have a heater? yes
What is the water temperature? 75F
What is the entire stocking of this tank? (Please list all fish and inverts.)
6 corys
6 bloodfin tetra
7 neon tetra
4 Odessa barbs
1 Betta
1 BN Pleco
1 Celestial Pearl Danio
5 chili rasbora
5 glowlight tetras

How often do you change the water? every 2 weeks
How much of the water do you change? 50%
What do you use to treat your water? Prime
Do you vacuum the substrate or just the water? yes

*Parameters - Very Important
Did you cycle your tank before adding fish? yes
What do you use to test the water? API Master Kit
What are your parameters? We need to know the exact numbers, not just “fine” or “safe”.

Ammonia: 0
Nitrite: 0
Nitrate: <20

How often do you feed your fish? 2x per day
How much do you feed your fish?
What brand of food do you feed your fish? Daily: flakes, pellets, bug bites, algae wafers at night. Occasionally: frozen shrimp & bloodworms
Do you feed frozen or freeze-dried foods? yes, as treats 1x week

Illness & Symptoms
How long have you had this fish? 6 months
How long ago did you first notice these symptoms? 24 hours
In a few words, can you explain the symptoms? Very healthy, active, young fish at evening feeding. The next morning he looked like he'd been in a fight -- huge ragged white patch on dorsal, smaller white scrapes on each side, half his tail missing. Hiding in the weeds, would not eat.
Have you started any treatment for the illness? no
Was your fish physically ill or injured upon purchase? no
How has its behavior and appearance changed, if at all? Appears traumatized. Hiding in the weeds the next morning & would not eat. As day progressed, he came out to swim a little. I was able to hand-feed him some frozen shrimp this morning.

Explain your emergency situation in detail. (Please give a clear explanation of what is going on, include details from the beginning of the illness leading up to now)

This young fish was the picture of health the evening before, zipping around the tank, flirting with the ladies, eating like a horse, beautiful colors, healthy fins. The next morning he looked like he'd been in a fight -- huge ragged white patch on dorsal, smaller white scrapes on each side, half his tail missing. He was hiding in the weeds and would not eat. I suspect he was attacked in the night by the Bristlenose Pleco, which I know has a peaceful reputation but I Googled it and they've been reported to attack goldfish, and this Odessa barb is the closest thing in size and color we have to a goldfish. I caught the pleco and put him into the quarantine tank as a preventive measure for the next night. This morning the barb is no worse and I was able to get him to eat a small amount of frozen brine shrimp. He's swimming out of the weeds a little.

My other thought was columnaris due to the symmetrical shape of the ragged white patch but it doesn't feel right. For this severe condition to appear so suddenly in the night yet not progress further over 24 hours doesn't seem like an illness. The fish is actually acting better this morning than yesterday morning. I became the keeper of this tank 2 months ago when my daughter went away to college. She had near constant water quality issues so I started changing it every 2 weeks 50% -- and perhaps more importantly as a clue to the BNP attack theory -- I cut back on feeding. I feed the daytime fish twice per day as much as they'll eat in 2 minutes, and drop in half a Hikari algae wafer, which is about the size of a dime, every other night. When I Googled "pleco attack" I learned that if they get very hungry they will go after other fishes' slime coats. Am I not feeding him enough? We've had him about 6 months. We got him at the same time as the Odessa barbs. All were juveniles at the time and have grown nicely. The BNC is about 5 inches long now. The Odessa barbs got their mature colors about 2 months ago and are all very healthy and active until this incident. Everyone else in the tank gets a long nicely, even the Betta.

We got some new corys and bloodfin tetras 3 weeks ago. All those fish were quarantined for 1 week and proactively treated with methylene blue, API General Cure and Kanaplex. All seem healthy and happy.

Here are pictures to go with previous post. The resolution isn't great. There are some white specs in the images that may look like ick but it's an illusion; he definitely does not have that.


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Are you sure it’s a scrape? It looks kinda fungal to me but it could just be the pic. If anything bullied it I would assume the danio
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Thanks for responding so quickly. The danio is a Celestial Pearl Danio -- less than an inch long and about 10% the mass of the barb, so I'm pretty sure it wasn't him. The pictures do make it look fungal, but the fact that this appeared overnight in the span of about 10 hours, then seems to have not progressed at all because he's a little more active after a day and eating a little, seems to me to say injury. I figured if it was an extremely aggressive fungus/bacteria to have moved that quickly that he'd be noticeably worse or even dead within a day. But I really don't know, which is why I'm posting it here. I appreciate your input.
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At the moment the stocking list has only celestial pearl danios Aggressive Aquatics I doubt they could do that at 1 inch long with their tiny mouths.

With just 4 Odessa barbs in a school that’s a possibility as you write he was flirting with the ladies that may be part of the issue as the fish mature into adults? .
The bloodfin tetras are also in a small school along with 6 other mid water schooling species. The blood fins are new to the tank.

Whoever did the nipping . Has gone in deep on the tail. That may not heal even with multiple water changes each week to avoid the infection spreading. . I fear that fish is in trouble. Trying to keep the water clear is the best option. Changing some water 45% every second day may help. In future 45% - 50% every week is my suggestion to keep the water clean.

I suspect the issue is to many small schools of mid water swimming fish starting to mature into adulthood.
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Sorry to hear but I seriously doubt a BN can cause these kind of wounds.
They are not hunters.
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Actually, the only one capable of doing this to the tail is the betta. Is it a male betta?
Wild guess, if the odessa male was flirting with females, its intense coloration and posture may have triggered a fight impulse in the betta.
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I would be feeding the pleco more than just an algae wafer every other night. Do you feed fresh veggies at all? Does he have wood to rasp on? I can't imagine a well fed BN pleco attacking any one.

I can't say for sure one way or another whether your big guy did this or not but I can imagine it if he is really hungry. Elbert, that handsome fellow over there in my avatar gets fresh veggies at least twice a week. On all the other days he gets veggie rounds, algae wafers or shrimp pellets and occasionally he gets blood or tubifex worms. .

They are docile creatures when fed well. His belly should be slightly rounded. If it isn't I have to think he isn't getting enough food and can see where it could lead to something like this happening. If it is slightly rounded then I would have to look into a different cause for what happened.

Hopefully your little barb will heal and be back to his frisky self before long. If your pleco didn't do it I hope you can figure out who did.
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Update: to my amazement, the barb is healing nicely and seems to be back to his old self behavior-wise. There have been no other incidents since removing the BNP. I witnessed an interesting interaction between the wounded male and one of the females. She was hovering in the water column and he swam slowly up to her then dipped his head, presenting the wound on his back to her, which had gotten ragged. She gently nipped off some of the ragged bits then swam away. He slowly pursued her, presenting the wound again. She declined to do any more cleanup and he gave up after 3-4 more attempts. The next day the wound was visibly better.

Following mattgirl's advice, I put some blanched spinach in the BNP's tank which went untouched for 24 hours so I removed it. I also gave him some extra algae wafers which also went untouched after a day. And these are the big wafers -- about the size of a dime, 30mm/0.75in in diameter. Fully hydrated, they expand to quite a large blob. And yes, he has wood. I attached two pictures of the BNP here; does he look healthy?


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I am happy to hear that your little barb is doing well. The interaction between the hurt one and the female was a very heartwarming thing to read about. Kinda tells us a little bit more about them. It seems that may more intelligent than we give them credit for.

If your BN has never been given veggies it may take some patience to get him to even try them. It was good that you took it out after 24 hours but if I were you I would just keep offering it until he discovers it is actually food. It could take weeks or it could happen at any time. I feel sure though, once he gets a taste of the veggies he will come running when you put a fresh piece in there. Until then put it in the same place every time. Once he discovers it you can put it anywhere in there and he will find it.

If this guy isn't cleaning up all of the wafer you are putting in there you will want to remove what he doesn't eat to keep from it fouling the water. I also suggest that you break the wafer in half and just feed half at a time.
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