Are my fish aggressive?

[mirandapayne]

Back in about April I started a fish tank. It included 4 Glofish and 4 guppies in a 15 gallon. However, about a month later the guppies passed away one by one. I found some of them in rough condition, some with fins missing. I assumed it was the filter because usually I would find them against it. I continued to take care of my Glofish and everything was normal and they all seemed healthy but I recently added 2 dwarf suckers. I noticed right away that one of the suckers were constantly hiding, it was rare I seen both of them in my view. Suddenly, about a week after adding the dwarf suckers, one of my Glofish suddenly died. It was missing half of a fin and even its eyes, but this time it wasn't found against the filter. I know both Glofish and dwarf suckers are supposed to be very peaceful fish but is it possible there's an aggressive one in the bunch? I read that Glofish can be aggressive if their not kept in a big enough group but shouldn't 4 be enough? Plus would they even kill off one of their own? The other dwarf sucker has also suddenly been hiding a lot more too, which makes me suspicious that they're afraid of the Glofish. Does anybody have any idea or advice?

 

[Naughts]

What species are the glofish?

 

[Jan Cavalieri]

My first tank was a community peaceful tank with all sorts of small to medium sized fish. I bought 7 zebra-striped danios (before I knew they probably would drive my very slow moving Gourami crazy) but instead what happened was that one or two of the danio's started chasing certain smaller ones of their buddies until they basically harassed him to death, couldn't get any peace or any food - just non-stop swimming. One by one they died. Then one day I saw the danios eating the fins off of one of my beautiful Gourmi's 3 x it's size! The Gourami died that same day and I remove the two evil Zebra danio's from the tank and into my 5 gallon hospital tank. Then during on water change I accidently dropped a lid on one of the two tiger striped danios and I killed it. The rest had a much more peaceful disposition by himself and I needed a hospital tank - so I moved him back into the main tank and never had any trouble with him attacking small fish again, and I'm sure it took two of them to kill the gourami as well - so he won't have any playmates because he can't be trusted but he's lucky I let him live at all.

So I would say what you have is unusual but definitely possible. Some fish are far more territorial than others and that's what usually makes them aggressive and, if they are the ones left to guard a patch of eggs they will also be very aggressive to other fish.

 

[seangee]

Four is not a big enough group. Most sources suggest 6, personally I don't keep any shoaling fish in a group smaller than 12. And yes, they will attack their own.

 

[yeti79]

What type of glofish do you have? There are danios (zebrafish; Danio rerio ) tetras (black widow tetra; Gymnocorymbus ternetzi) barbs (tiger barb; Puntius tetrazona) and sharks (rainbow shark; Epalzeorhynchos frenatum) All of them except the shark should be kept in groups of 6 plus and will gladly school with their original versions the same as the glo variety. Add a few more and you should see less aggression.

 

[Indigo_Betta]

What do you mean by dwarf suckers.... if they are Chinese algae eaters they would most definitely be attacking the glofish. For your school of glofish, at least 6 is ideal, but 5 can work.