we have one aggressive guppy?

I have never known female guppies to be aggressive unless they are outnumbered by males. But males can be aggressive in a single sex community. If they have long flowing tails, bright colours along the sides and are generally slim (especially on the belly) they are most likely male. Males also are sold a lot more than females as they are generally more colourful and catch buyer's eyes.

Other than that there are a few reasons why the fish may be attacking the others.

1) The others have a disease. I have seen numerous times that other fish are ill or have a disease and another one will attack it. However in this case it is unlikely that only one doesn't have it.

2) Lack of food. Guppies want a lot of food, and can eat it comfortably. However there is still a rule of thumb. Note how long it takes them to eat the food, they should be fed as much as they can eat in two minutes - twice a day. Some people say every other day, others say once a day, however I have always fed my adult fish once a day and my baby fish twice a day - and have a very low mortality rate. By the way, for anyone with other fish who are thinking their fish are eating too much in the two minutes get guppies. Some friends of mine have found that placing two guppies in a tank helps control what the others eat without dying themselves.

3) Stress. Either the water conditions are wrong, or he/she simply didn't accept the transfer so well. It is a shame but the latter does happen. Some fish just can't take the transfer.

4) If it is a female - it could be the others are male and it is being harassed too much, which can either lead it to hid constantly or fight back.

In any case the best course of action is to remove the fish and see if petsmart will exchange it or a friend has a fish tank that wouldn't mind a potentially aggressive guppy - mollies can and will hold their own. I would recommend getting some more guppies for your last one to have some company, although one more could be sufficient. If you want more than that and want a mix of sexes, remember to have 3 females to every one male. It helps with birth control and it allows the females to be less stressed.

Separate the aggressive one in a bowl of the water for a few days, see if the other fish improve.

Although the guppy may not have killed any of the other fish, you are not supposed to add 6 fish at one time, the water is supposed to take a few fish at a time to prevent it being polluted. For example the bacteria that breaks down the poo needs to build up, 6 fish in one go may have polluted the water

hi, i'm uncertain approximately your tank set up. are there any plant life in there? its the two she isn't delicate along with her associates or something is coming up stress for her. appears like it will be approximately yet another week earlier she supplies beginning. what you're able to do to shop her fries. a million) determine that she is easily fed such that she will have not have been given any urge for foodstuff to eat her toddlers. 2) uncertain if the tank is thoroughly empty now. in case you ought to cut up her, try this. you do not ought to purchase a sparkling tank. get 2 plastic containers. considered one of which has holes on the backside and factors. this plastic basket must be smaller than the bigger one yet not too small surprisingly plenty greater healthful.placed this plastic basket over the bigger field. this could act as your fry tank... the holes will enable the fries to pass to the backside or swim remote from threat. with the female being stored at bay. place the female interior the basket with holes.make specific water point is there and adequate space for her to swim.. do placed some aquatic plant life in it. use a number of the previous tank water once you place up this. this could act to calm her down. in case you're in singapore, i will spare you some japan blue guppies... suitable for small tanks.. they don't improve too great for guppies.