Fish behavioral changes after adding (or removing) other fish?

[hunterisgreat]

So I added a pygmy caribbean filefish a week ago and I've noticed my ~6-12 months existing scrawled cowfish has begun to remarkably come out of his shell. Somehow he/she has gotten a confidence boost... used to always hide when I came in the room but now seems indifferent or even curious of my presence. I've also noticed the cowfish seems to pretty much school around with the filefish... the filefish is pretty shy right now.

Is it normal to have large changes like this? Is it a good thing or potentially indicative of something bad that on the surface seems positive?

 

[CStrickland]

People call that a "dither fish." In my tank it was my fang blenny, he's not scared of anything and once I added him it was like my chalk bass realized there was no reason to be hidey. I've heard of people using other fish the same way to coax out shy guys by example, it might have been chromis, not sure.

 

[hunterisgreat]

People call that a "dither fish." In my tank it was my fang blenny, he's not scared of anything and once I added him it was like my chalk bass realized there was no reason to be hidey. I've heard of people using other fish the same way to coax out shy guys by example, it might have been chromis, not sure.

Interesting. Ironically I have a wild caught blenny that has tons of personality but he hasn't influenced anyone. I guess because he's on the bottom unlike the cowfish


Sent from my iPhone using Tapatalk

 

[BigEZ77]

I added two fish last week (6line and damsel), now my larger clown has become more aggressive with the smaller clown and my Royal Gramma is out all the time (used to spend most of the day in his cave)...I think mainly because he's protecting his space against the damsel...seems to rush at him quite often.

 

[scooter31707]

I agree. I think it's the fact fish are protecting their territory and it's also a dominant personality also. I think if they are in their cave they made be scared of a certain fish in the tank. I think the majority of the time it's part of their nature in the wild. If you take out a dominant or nuisance fish, that means another fish left in the tank will step up and take over the "king" of the tank role.

 

[hunterisgreat]

Yeah thats sort of why I was asking if there was some negative behavior that wasn't obvious or looked to be a good thing at first glance. I train dogs so I'm pretty good at reading posturing and similar behaviors in all sorts of animals and I don't think this is happening with my cowfish. He has never hid all the time... normally always out and about foraging but when I came in the room, particularly if I came in abruptly or fast, he'd position himself behind a rock with just his eyes exposed so he could watch me. Now its like he's abruptly lost his fear of me... will come up to the glass and just stare me in the face. Interestingly when I'm feeding him and the new filefish sit there and eat together peacefully... no fighting over the food or anything. Its really interesting. I dunno if its because they are sort of similar in their locomotion or something else but they seem to like each other. The filefish hides when I come in the room (and turns on a side so he's giving me the slimmest profile of him from overhead to seem smaller while keeping his eyes glued on me). I have a new tiny tiny butterfly fish that seems totally oblivious to everything and just forages away all day long.

 

[PatW]

Fish interact constantly. I had a large blue green chromis that acted aggressively towards my anthias. I later added a small blue green chromis. The large chromis really did not like the small one and attacked it often. But the small chromis was very fast and alert. After awhile the large chromis gave up on its attacks. Interestingly enough, it ceased harassing the anthias. Right now, the situation seems stable.

 

[Sk8r]

Many people make the mistake of getting a lot of bright, pretty little fish, then add some centerpiece fish, a large pushy one, and all the other fish disappear into the rockwork except at feeding. If you balance sizes and pushiness you get a much more active (and happy) tank.

 

[hunterisgreat]

Many people make the mistake of getting a lot of bright, pretty little fish, then add some centerpiece fish, a large pushy one, and all the other fish disappear into the rockwork except at feeding. If you balance sizes and pushiness you get a much more active (and happy) tank.

Yeah thats what I'm trying to do here... part of the reason I took a while to add anything and why I added what I did was my cowfish (I love cowfish) was so shy and I didn't want to make it worse. So far I've had no issues between fish, its just been they were scared of me lol. I guess in a 210 a few inch or two long fish have more than enough places to hide and aren't ever "forced" to deal with me being in the room lol