SHOP TALK : Making an Informed Choice of Possible Pets : There are many options at many prices if you decide to expand your household with a goldfish, hamster or mouse.

A fear of many a parent: Your child wants a pet for the first time.

You attempt to negotiate. He or she wants a St. Bernard, you offer a goldfish. He or she says, maybe a German shepherd. You suggest a goldfish. Your child says how about a cat? You say, OK, a goldfish . . . or maybe a hamster or a mouse.

We’re rooting for you, so last week we visited four Ventura County pet shops--Petco and Animal House Pets stores in Ventura, the Pet Company in Camarillo, and Pet World in Oxnard--in search of a goldfish, a hamster or a mouse.

We began by looking at the fish. All we knew was that when selecting one it was best to avoid those floating at the top of the tank, upside-down. Other than that, to us a fish is a fish is a fish.

Not so. True, there is such a thing as a basic goldfish, but there are enough types of other goldfish out there to make your head swim.

The cheapest, simplest pet goldfish--the kind you’d be able to pick up at a county fair by bouncing a Ping-Pong ball into a bowl--is perfectly acceptable. At Pet World they are referred to as “regular” gold fish. At Petco they are “feeder” fish because they are used to feed other fish even though they are the most popular among the store’s average goldfish buyers.

At Petco, the basic “small” goldfish went for 29 cents each when buying quantities of one to nine, 10 cents each when buying 10 to 99, and nine cents each when buying 100 or more. At Pet World, the regular small gold fish were also 29 cents each, or 15 for $1.

Next up on the goldfish social ladder are the orandas ryunkins, liontails and fantails. They all have different price values placed on them, depending on breed and size. It just depends on how much you want to spend and whether you are a serious collector or just want a low-maintenance household pet.

We found fantails for $2.99 at Petco, and for $3.98 (marked down to $2.98) at Pet World. We found a red oranda for $5.99 and a red cap oranda for $6.99 at Petco. At Pet World we found a regular oranda (medium-sized) for $5.98, a medium African oranda for $4.98, and a small African oranda for $3.98. And at the Pet Company we saw a red and black oranda for $9.99. It pays to shop around.

A very popular kind of goldfish is the koi. You’re apt to find a koi just about anywhere fish are swimming in tanks. Petco had them at $19.99 (large) $11.99 (medium large) and $7.99 (medium small). Pet Company had them for $24.99 (large) and $5.99 (small). And Animal House had small koi for $4.99. Keep in mind that there are relative degrees of large, small and medium.

By the way, Pet Company specializes in exotic fish and even if you’re not buying, it’s a great place to window shop. They’ve got some pretty amazing fish. Our favorite? The dogface puffer ($29.99). And the fumanchu lion ($39.99). A fumanchu lion was going for $24.98 at Pet World. So again, you can see how prices can vary greatly depending on various factors.

Now that we’ve confused you, let’s try to straighten things out. We spoke with Kristen Steinbrecher of Petco for advice on selecting healthy fish.

“Look for where the fish swims in the tank. If you see a fish sitting at the bottom, that’s not a good sign. If you see a fish hanging around the top where the filter is, that’s not a good sign either. Those are signs of disease,” said Steinbrecher. “As a rule of thumb you want fish swimming around the middle, not just sitting or hovering.”

She also said to check the fins for white spots, a fish parasite known as ich. “Also look for fungus hanging off the fins or certain parts of the body. Look for bulging eyes. Some fish have bulging eyes, but the majority of them don’t.”

Goldfish are fairly hardy, said Steinbrecher. But keep in mind that “feeder” fish are not maintained as well as others because they are used as feed.

If the kids won’t let you off with a goldfish, try a hamster. We found a basic one for $4.99 at Petco. The store also sold a Siberian hamster for $22.99. At Animal House Pets, a dwarf hamster was $14.99. And at Pet World a dwarf hamster was going for $10.99. If you prefer mice, we found them for $1.99 at Petco, $1.69 at Animal House and $1.49 at Pet World.

If none of these satisfy the kids, there’s always the increasingly popular green iguanas, which can cost anywhere from $19.99 to $49.99. “You want them with some meat on them,” Steinbrecher said.

Or you could just give in and buy that St. Bernard.