In Your Experience, What Have Been Some of the Most Problematic Fish?

[duanes]

To me Leporinus is one of the"the" most misunderstood species, and its not the fault of the fish, but the aquarists, and the misleading available info.
This is not a normal community tank fish., no matter what the care sheets tell you
To hold down aggression, they need to be kept in a shoal of at least 6 or 8, so trying to keep them as a pair or trio, is usually useless.'
And keeping them in tanks of under 6ft is another bad move, I've seen them recommended for 75 or 90 gal tanks, to me this is delerium.
They also come from fast flowing water in rheophillic currents which helps dissipate aggression, so a tank with only HOB or canister filtration is totally inadequate.
A 6 ft tank with a shoal of at least 8 with Couple high velocity power heads or wave makers would be a minimal way to house them to me.

But this is the only way I'd keep cichlids like Geophagus, as they are from similar habitats, and also shoal.

 

[jjohnwm]

Problematic fish? Interesting question.

I have never really had problems just keeping fish alive and healthy, but then again I have never been drawn to the challenge of keeping fish simply because they are known or thought to be difficult. I keep fish that I like; if they happen to be common as stink, and/or extremely easy to maintain, then I just lean back and enjoy it.

If I find a fish to be problematic, well, there's usually another fish in the next tank who will deal with the problem quite handily.

Problems for me tend to be centered around fish that breed too prolifically, forcing me to break out the blender and start mixing up another batch of Fish Jello. This is pretty much limited to livebearers, cichlids and, lately at least, goldfish. I don't enjoy this task, but it's a necessary evil.

My Electric Cat, way back in the day, gave me such a jolt once when I was being a little careless in his tank that I reflexively yanked my arm out and put my elbow through a plate glass tank cover leaning nearby. Still have an ugly scar on my upper arm as a reminder. Problematic?

I never got a serious shock from an Electric Eel that I had for some time, but honestly, I was so dang paranoid dealing with that thing that I am certain my blood pressure was way too high for those several years. Problematic?

I've never had any interest in Piranhas, but while working at a LFS while in high school, I again got careless and had my hand in the water at the wrong time when something spooked the whole school of them; I got a slice on my finger that was deep but so clean and fast that I didn't even feel it, just saw blood in the water. Don't like Piranhas, never wanted any...still get bit. Problematic, yes...my carelessness, though, not the fish's fault.

I think if I had to choose one species, it would be native Grass Pickerel, Esox americanus. I thought...and still think...that they were one of the coolest natives I could catch, and I collected them locally on a number of occasions. I simply could not get them to coexist with one another; the best outcome would be that they ate each other until I had only one left. Quite often I had none left, as both eater and eatee would end up dead, and on at east one memorable occasion, three last survivors in a tank...all very close in size...had seemed to sign a truce and were living well together...or so I thought...for months. Then one day they suddenly ended up as a sort of nesting-dolls arrangement, with one inside another inside the third, all quite dead. Larger tanks, more plants, more hardscape, different lighting...nothing seemed to matter. They were cannibalistic lunatics..."I'm gonna eat you"; "No, I'm gonna eat you!"; "Oh, yeah? Well, I'm gonna eat both of you!!!" I can't imagine how the species breeds successfully. I shudder to think how many of those fish I caught, brought home, and lost over a period of several years before I finally admitted defeat and gave up on them. I kept the last one alone for several more years before losing it to unknown causes, and never collected more after that.

So I suppose that fish is my Waterloo.