Hi i have one of these vacumme gravel cleaner and just wondered am i safe using it with the fish still in the tank or should i be transporting them to another tank whilst im cleaning thanks.
No you don't need to move the fish. Moving them would probably be more stressful for them using the gravel cleaner. Always keep an eye on what you are doing, to make sure you don't suck up any fish, but most tend to stay away from the gravel cleaner in my experience.
The only fish I move out when using a gravel cleaner is my betta and that's because I do 100% changes on his bowl.
I have guppies and platys and the guppies seem to like the gravel cleaner a little too much and dont get out of the way so its quite a task to try and keep them out of harms way but ive managed the both times ive used it and hell it does a great job of the gravel even takes away the green algae build up to a extent