Are Brackish Fish Agressive ?

[kanzaris]

Hi

I started a brackish tank about six month ago. I bought one archer, two monos, four scats and a shark cat
and four knight gobys. The shark cat keeps himself to himself and the knight gobys get on alright with one another and the other fish. But oh my god the scats keeped beating each other up so bad one by one I had to bring them back to the shop,and when I had only one scat left he started picking on the other fish. The same with the monos.Well i got one mono left and he seems ok by him self. The shop is good enough to take the fish back because they know me. Now I bought two Funky Gobys and they where ok together but the last two days the bigger one started chasing the smaller one like mad and he lost all his colour.
Could somebody tell me am I just unlucky with the fish or are they just agressive fish ?

All suggestions would be appreciated.

Sabs

 

[pica_nuttalli]

well, for starters, what size tank have you got? sounds to me like you're have territory conflicts...

(btw, "are brackish fish aggressive" is kind of a silly question. it's like asking "are dogs big?"--some of them are and some of them aren't and it really depends on what your definition is.)

 

[nmonks]

Hello sabby --

While you have a great selection of fish that do enjoy the same water conditions, you don't have the right numbers.

Colombian sharks should really be kept in groups, not singly. Kept alone they become rather nervous. While you may be OK provided the other fish don't harass it, I'd recommend buying at least one more specimen. On the downside to this proposal, they do get rather large, typically around 15 cm in captivity, but sometimes a little bigger.

Monos, archers, and scats naturally live in groups in the wild, but in captivity this can be problematical. As you have observed, though shoaling fish, they are also intensely hierarchical, and the dominant fish can bully subordinate fish to the point of harming them, even killing them. It is sadly quite common for people to buy a groups of archers or monos and then wind up with just one. I haven't heard about this with scats yet, but that doesn't mean it doesn't happy. I think archers are the worst, and always recommend they are kept singly.

The problem was that you bought too few fish: had you bought six scats they would have gotten along just fine. It is just when you have two or three of them, the aggression is "concentrated" on just a few specimens, who suffer. In a big group, the bully (dominant, or alpha, fish) in the group can't harrass just one specimen and his aggression is split up among all the other fish.

I've personally kept four monos and seen them get along fine, and I'd suggest that as a minimum number if you want to have another go. If not, provided the single scat and single mono are feeding and otherwise happy, I wouldn't worry about them for now.

I have no idea what "funky gobies" are; can you describe them? Gobies are not (usually) shoaling fish but tend to be territorial instead, and if your aquarium is too small, yes, they will fight.

Cheers,

Neale

 

[kanzaris]

Hello sabby --

While you have a great selection of fish that do enjoy the same water conditions, you don't have the right numbers.

Colombian sharks should really be kept in groups, not singly. Kept alone they become rather nervous. While you may be OK provided the other fish don't harass it, I'd recommend buying at least one more specimen. On the downside to this proposal, they do get rather large, typically around 15 cm in captivity, but sometimes a little bigger.

Monos, archers, and scats naturally live in groups in the wild, but in captivity this can be problematical. As you have observed, though shoaling fish, they are also intensely hierarchical, and the dominant fish can bully subordinate fish to the point of harming them, even killing them. It is sadly quite common for people to buy a groups of archers or monos and then wind up with just one. I haven't heard about this with scats yet, but that doesn't mean it doesn't happy. I think archers are the worst, and always recommend they are kept singly.

The problem was that you bought too few fish: had you bought six scats they would have gotten along just fine. It is just when you have two or three of them, the aggression is "concentrated" on just a few
specimens, who suffer. In a big group, the bully (dominant, or alpha, fish) in the group can't harrass just one specimen and his aggression is split up among all the other fish.

I've personally kept four monos and seen them get along fine, and I'd suggest that as a minimum number if you want to have another go. If not, provided the single scat and single mono are feeding and otherwise happy, I wouldn't worry about them for now.

I have no idea what "funky gobies" are; can you describe them? Gobies are not (usually) shoaling fish but tend to be territorial instead, and if your aquarium is too small, yes, they will fight.

Cheers,

Neale

 

[kanzaris]

Hello sabby --

While you have a great selection of fish that do enjoy the same water conditions, you don't have the right numbers.

Colombian sharks should really be kept in groups, not singly. Kept alone they become rather nervous. While you may be OK provided the other fish don't harass it, I'd recommend buying at least one more specimen. On the downside to this proposal, they do get rather large, typically around 15 cm in captivity, but sometimes a little bigger.

Monos, archers, and scats naturally live in groups in the wild, but in captivity this can be problematical. As you have observed, though shoaling fish, they are also intensely hierarchical, and the dominant fish can bully subordinate fish to the point of harming them, even killing them. It is sadly quite common for people to buy a groups of archers or monos and then wind up with just one. I haven't heard about this with scats yet, but that doesn't mean it doesn't happy. I think archers are the worst, and always recommend they are kept singly.

The problem was that you bought too few fish: had you bought six scats they would have gotten along just fine. It is just when you have two or three of them, the aggression is "concentrated" on just a few
specimens, who suffer. In a big group, the bully (dominant, or alpha, fish) in the group can't harrass just one specimen and his aggression is split up among all the other fish.

I've personally kept four monos and seen them get along fine, and I'd suggest that as a minimum number if you want to have another go. If not, provided the single scat and single mono are feeding and otherwise happy, I wouldn't worry about them for now.

I have no idea what "funky gobies" are; can you describe them? Gobies are not (usually) shoaling fish but tend to be territorial instead, and if your aquarium is too small, yes, they will fight.

Cheers,

Neale

Hi Neale
Thanks for the advise. I noticed that the columbian shark is rather shy and I wondered that such a big fish is acting like this. So now I know why. We had two at the starting but thought that the tank was to small. The other fish don't pick on him.Funny enough the knight gobys (I have 4) are the most peacefull fish in the tank.
The so called funky gobys ( thats what the shop said they are) are fighting, well the bigger one is chasing the smaller one. They are hard to describe sort of yellow with brownish stripes across the body more long only the face lookes like a goby and they dig right into the gravel. By the way my tank is 4ft 180 ltr and i am starting to think its to small for brackish as they are so territorial. We are planning to get a bigger tank about 300 ltr. At the moment the fish seem to be happy. My two Orange Chromides are trying to breed.
Two more questions !!!!!!!! PLEASE !!!!!!!!!
I also got a green spotted puffer I had him for about three month now .When I first got him he was a greedy little thing. He still eats put at feeding time he is more interested in going up and down in the bubble wall he spends most of his time there. Could it be that he is intimidated by the other fish specially the gobys at feeding time as they are a bit agrassive and he looks as so he cant be bothered with all the hassle.
Last thing I also got a (Shop called it a croaking toad fish) any tips on him ? He is feeding ok on prawns and mussles. I know you have to be carefull when handling because of the poison. Please excuse my ignorance regarding brackish fish, I am in to chiclids and when I was given this 4ft tank someone talked me into starting up a brackish tank. Your advise is greatfully received.

Thanks a lot
Sabby

 

[aquamanA]

seams one hell of a story there jeez I had a fish who would beat the crap out of another fish just need to know when to buy the right ones I guess good luck with it man...

 

[nmonks]

Luck doesn't come into it (much). By and large, fish behaviour is very predictable, and given information on the size of the tank and the other tankmates, 90% of the time it is pretty easy to say whether a new fish will fit in or not. There is the odd psycho fish, to be sure, but usually you know which ones school peacefully, which ones hold territories, which ones are fin-nippers, etc.

Cheers,

Neale

I guess good luck with it man...