Non-specific sick fish - remove?

[Linwood]

I have a 45G planted community tank, with 5 longfin red serpae tetra, 2 angels, 1 BN pleco, 1 raphael catfish, numerous shrimp and snails. Previously I had 5 congo tetra in there but they were a bit too aggressive during feeding so they moved to a larger home. Cycled, good water.

One, and only one of the tetras is about half dead. For weeks now he has slowed and eventually stopped eating, swims nose up, lost a lot of color and weight. It came on gradually, he ate less and less (thinking intimidation was a role I moved the congos).

There are no other symptoms, no sign of parasites, he's half transparent so no large ones internally. No flashing, no deformity, no unusual swimming except he is about 20 degrees nose up most of the time (but still roams the tank, and still reacts quickly to the infrequent harassment of his mates). He now ignores food, all food (even bloodworms the others swarm for). I've reviewed lots of fish disease sites and nothing definitive seems to match.

My guess is he is just going to die, maybe it was his time.

So here's my question - given there's something undiagnosed going on, do such things generally get more contagious over time? It's way too late if it was particularly contagious now.

My wife would not like to see him disposed of pro-actively, but I am leaning in that direction. Please note I am not asking an ethical question, there's no "right" answer to such.

I am asking whether most fish diseases that might fit this description become more dangerous nearer death; is any protective purpose served by removing him pro-actively at this point?

 

[Delapool]

Interesting question.

First up I think this why the QT was invented.

In general though I would imagine that as an infection gets larger there is more risk of it spreading through the tank. Probably the largest risk would be if say internal bacterial infection (just saying), fish dies overnight and then other fish have a go at him.

 

[Linwood]

Interesting question.

First up I think this why the QT was invented.

In general though I would imagine that as an infection gets larger there is more risk of it spreading through the tank. Probably the largest risk would be if say internal bacterial infection (just saying), fish dies overnight and then other fish have a go at him.

Well, I use a QT for bringing in new fish, but I get your point. But right now I have 5 other fish in the QT and so that's out, no point in adding them to the risk.

And about "goes at him" is a good one, I had not really considered that aspect of the issue, and I think it's a deciding factor.

 

[Delapool]

Well, I use a QT for bringing in new fish, but I get your point. But right now I have 5 other fish in the QT and so that's out, no point in adding them to the risk.



And about "goes at him" is a good one, I had not really considered that aspect of the issue, and I think it's a deciding factor.

Yes, can't be too careful sometimes.

I had neons catch columnaris one after the other. It didn't seem like more fish got infected slower or faster, it was just a steady progression through the school.

 

[Linwood]

I had neons catch columnaris one after the other. It didn't seem like more fish got infected slower or faster, it was just a steady progression through the school.

And I am a bit concerned, it may be that I'm looking for it, but the other 4 tetras are seeming less and less interested in food also. But they are all swimming actively and act normal, so hopefully whatever it was has not spread.

The dying one (now disposed of) was not only swimming nose up today, but quite sideways as well. But a close inspection when he was out of the water still showed no overt issue - injury, parasite, deformed scales or fins, fungus or discoloration; just very thin and transparent.

 

[Delapool]

Are they getting stressed by the angels or anything is all I can think of. I shifted cardinals to a small tank and they seem more happy / not battling high water flow.

Hope they pick up.

 

[Linwood]

Not in any obvious way, the 2 angels are unmated and have been in there for several months. During feeding the angels get to the top first and eat, but plenty of food falls through below for the tetras. There's plenty of room, a fair number of plants.

There is a fair amount of water flow, but it is a good sized tank, I am sure they can find dead areas. There's a spray bar at one end aimed along the tank; the intake is just behind the bar.

I was worried the congo tetras were a bit too aggressive when feeding, and they would go lower and directly compete, which is why I moved them out (maybe 3-4 weeks ago). Partly motivated by this one tetra that never seemed able to get food. Afterwards when it was a bit less hectic it became clear he was just not interested in food.

Tank is on a timer, 2 x 4 hour periods, in a quiet part of the house (my office). Clear water, good chemistry.

What I see now may be more normal; I've got angles and congos to compare it to, and they are such aggressive eaters. Will just see how it develops.

Oh... these four (unlike the other) have good red color, nice long fins that are nicely black, which is a good sign.

 

[Delapool]

It all sounds good

I had the same. The angels, rosy barbs, loaches and even mollies would all madly rush in for the food while the bn catfish were sitting underneath.