The humble goldfish is as smart as a cat or dog, can live more than a decade and can even count, a Perth researcher believes.

And yet, she says, often owners do not give them nearly enough love and care.

Miriam Sullivan, a Lecturer from the University of Western Australia who is passionate about pet fish, has just completed a PhD on the subject.

She surveyed 600 fish owners, analysed people's responses to the suggestion that they clean their pets' tanks, and conducted her own research into whether goldfish prefer real or fake plants in their tanks.

Dr Sullivan found that people who watched a video encouraging them to clean out their fish tank more often were more likely to get better at cleaning their tank in following months, but only if they intended to improve.

"It shows us that often we only need a small trigger to change our behaviour," she said.

"Now, I don't think a one-minute video will change your behaviour permanently, and it can't force you to change if you are very fixated on that behaviour, but if it's something that you're trying to do already, it can be really helpful."

Fish lifespan can match puppy, kitten

Dr Sullivan described fish as the "forgotten pet" which, if cared for properly, could have a life span as long as a kitten or puppy.

"They can feel pain like cats and dogs, and we keep them as pets, so we're responsible for their welfare," she said.

"On the surface it looks like there's no real difference, but people don't seem to care for them as much, and that's partly because they're not fluffy and cute, they can't bark at you to tell you they're hungry.

"But also it's not intuitive, so with your cat and dog you know if they're hungry and thirsty because they show the same behaviour you do when you're hungry and thirsty.

"But intuitively it's very hard to think about what it's like to live in dirty water."

Dr Sullivan said the fish demonstrated a marked preference for having a plant, either plastic or real, in their tank.

She said earlier studies had shown fish were able to remember important information, cooperate with each other, solve mazes and recognise themselves in mirrors.

Dr Sullivan has urged anyone planning on getting a pet fish for themselves or children to do their research.

"People thinking about getting fish as pets should find out as much about them as they can," she said.

"They can Google information and there is a lot out there.

"They can talk to people who already have fish.

"People need to take responsibility for their pets and new owners run the risk of not knowing a lot of important information."