Yep stats are fine, sorry to be pedantic on asking but 9 times out of 10 people say stats are fine when they arent, so we have to check.
The tank is 30 gal give or take, so in theory yes, it could take a shoal of 6 of each of the barb species, the minnows are sort of temperate to coldwater, so they don't really fit, theres relative principles of o2 saturation in warmer water to consider, you wont get them to full longevity in tropical temps,also theres the factor of a coldwater fish in warmer temps, they tend to dominate tyhe oxygen, they need more than warmer water fish, and if the barbs are kept at low temps they won't digest food properly and will be susceptible to disease, though they are tough fish and do usually survive suboptimal temps for long periods. What average temperature is your tank? What make and model is the filter BTW?
Probably worth a picture of the sick barb if you can get it, its obviously worth further investigation. Where is the weight loss most visible, indented stomach, skeletal features, thin at the caudal peduncle? Sorry bout all the questions, but we'll have to start narrowing it down.
The were probably talking suboordinate stress and sublimated behaviour due to the shoal situation, or possibly internal parasites. If he just small rather than thin it could be a developmental issue, and suboordinate stress can cause that. Might also be that you concievably have a non viable fish, tiger barbs are widely captive bred, the genes arent as strong as they used to be, not all make it to old age. Any physical traits that would increase the likelihood of that, albinism, hypermelanism or a particularly short body shape or longfin traits, stuff that would indicate a very limited genepool?
Certainly internal parasites are worth looking into on the weight and reluctance to feed, but that wouldnt explain the heavy respiration, thats going to be something chemical in the water, if as you say the gills are literally undamaged. Even gill flukes would show small spot wounds or areas of lost circulation in the lamellae. Mycobacterium can affect a fish quite assymptomatically at times but by now I wouldnt imagine he'd be the only sick fish. Makes me wonder if the poor respiration is about a vitamin deficiency either directly from malnutrition caused by suboordinate stress or a problem with lacking biotin, and thiamin. Do the barbs get much in the way of frozen food? Whats the primary diet?
We have had him for about a year and he has always been smaller than the other two, his body is quite short. The fish are regulary fed flaked fish and have blood worms about once a week, no frozen food at all. They also like to nibble the plecs algae wafers. Do you suggest varying this diet a bit more? If so what would you suggest? Thanks for all of your info so far, I'm glad I've found someone who knows what they are talking about!
Your welcome. Actually the diet doesnt sound half bad, hes getting a spread of vitamins (brand depending of course) and hes getting fibre, and some real animal protien apart from shoal size and the WCMM's it doesnt sound like anything is really off. Tiger barbs are usually one of the easier species to take care of both chemically and nutritionally, and ceertainly you seem to be meeting and exceeding minimal standards for health, so I'm leaning to a slightly genetically unfit fish or a very suboordinated fish being the root problem. As linz posted, a bit of fresh is never a bad idea though. I was half expecting a monotypical diet of flake or bloodworm, and thankfully its not that.
You can deworm your fish, panacur or praziquantel would do it, but the other minor factor to think of in body fat, the fishy version of severe cholesterol is hepatic lipidosis. Literally fat accumulated in the liver, the liver and the kidneys are linked, and in turn they are linked to respiration, both by waste transit, osmosis, salt regulation, and digestion. Fish with severe hepatic lipidosis do sometimes manifest poor respiration, but it would be a highly unusual symptom, dropsy is far more likely. That dropsy risk in mind, deworming could help the fish or finish it off, nearly all dewormers work in conjuction with liver function, they actually use the liver to create and filter parasite killing toxins, it is a biologically stressful process to a fish, and therefore it can be left too late. If the fish is very weak before treatment its survival is doubtful. Otherwise healthy fish tend to tolerate it easily.
What makes it more likely is a suboordinated possibly dwarfed fish may have organ compression issues anyway, then add to that they tend to only break stress induced starve periods by doing things like eating bloodworm and nothing else, and then you get vitamin imbalances. Biotin and vitamin A levels drop, the gill integrity and tissue replacement rate drops, gill tissue suffers invisibly unless your looking under a microscope, the digestive balance goes with the low personal o2 level , and you have a cyclical catch 22 starting up. Badly breathing puking fish. Ironically the cause can be body fat plus organ compression, plus vitamin imbalance. All caused initially bu stress, then become a severe physical problem. The irony is, you can actually have a skinny fish with a liver packed fatter than that of a foie gras duck, as the liver function fails the fish gets sick and loses weight. The fat cant be metabolised out of the liver, so even when the fish is skeletal and looks like its dying of malnutrition the liver is still enlarged and fat.Its a bit like an 8 stone 6 foot human who eats nothing but chocolate needing a bypass at age 25.
I know all that is probably a bit confusing to read and seems a bit self contradictory in places, but fishs organs are all co-dependant for functional efficiency. What might have started all this off could have been nothing more than a behavioural problem brought about by the way tiger barbs shoal dynamic works in small numbers, then it affects the animals feeding pattern, and you get problems.Or the one thing you can do the least about, which is an non-viable genetic specimen.
You have options of course. Segregation so that low rank pressures are removed, together with specialist dedicated feeding exclusively for him, making sure he cant pick and choose, or a larger shoal. I have the feeling you might just have a lone duff tiger barb though. It does happen.
If you do choose to deworm the fish, be prepared for the fact that even if the problem genuinely is worms , roundworm, tapeworm, even a liver fluke causing damage, the fish might not survive.Sad fact of life, but you often will lose the first badly parasitised fish. Theres yet another catch 22 in deworming fish, fish take these meds rather worse than mammals do, it kills a fair proportion, and no dewormer for fish in entirely safe, so much so in fact that routine deworming is rarely done, but the fact remains the healthier the fish, the larger the fish, and the less in need of deworming it is, the more likely it is to survive that deworming. I would have suspected the fish was actually anaemic, that would certainly affect the way it breathes and feeds, and its size, but if it takes bloodworm, they do contain haemglobin and iron, so perhaps not.
Actually , the more I think about that the more anaemia is making sense.Xanthopterin levels might be a problem. Perhaps try a little finely chopped raw lambs liver in the diet, or a few chopped maggot pieces, just the usual fishbait maggots, but watch they havent been fed on colourants or anything nasty. A few chopped castors would probably do the job too. Might be a duff fish with an iron balance problem, but we might as well have a go at fixing it, its not that much work.
I am very impressed with your response LHG, your comments are incredibly enlighteneing. AS I try to learn more about my fish it is great to get indepth information like this. This afternoon I separated him and gave him some food, he wouldn't touch it and now he is not swimming at all, just lying on his side. I fear he is suffering so think maybe it's time to euthenise him? What do you think?
Does sound like he's on the way out. I take it you know about clove oil about 10 drops per gallon, whisked well, fish dropped in, knocks em out in seconds, leave em there for an hour he wont be coming back.