Pet Q&A: Fat fish | Castration | Widowed budgies

Vet Stuart McMorrow answers your animal questions.

My goldfish has got very fat. Is it ill or could it be eggs?

Quite a few conditions can cause a fish’s stomach to swell which can look as though they’ve put on weight. Fluid in the abdominal cavity (known as dropsy) can be caused by lots of different things, such as a bacterial infection that affects the circulation, liver or kidney problems. An excess of fat in the fish’s diet or out of date food can affect the liver and constipation can also cause a swollen abdomen. I’d suggest you take your fish to see your vet.

I need some advice on castration. My five-year-old Rottweiler has quite a nervous disposition, would it help to calm him without changing his loveable character and energy levels?

Vets recommend getting pets neutered (called castration for male dogs) as this will prevent unwanted litters from adding to the thousands of pets already in rehoming centres. It’s not possible to tell in advance whether the procedure will have an effect on your dog’s temperament, as all dogs react differently. The best person to speak to is your vet.

I got two baby budgies about four years ago, but recently I came home to find my male budgie dead in the aviary. The hen seems to be coping OK, feeding and preening still. I’d like to get another companion for her but I’m worried they’ll fight.

Budgies are very social birds and they can get lonely if kept on their own. As your hen is still quite young it is a good idea to introduce a new companion. Another female would be best as this will reduce the likelihood of aggression.