Keeping jumpers in during cleaning/maintenance

[kamehameha]

I am planning to get a purple firefish in the near future and have seen a lot of mention that they are jumpers. I have a canopy on my tank so day to day that shouldn't be an issue.
I am just wondering, what's a good way to keep jumpy fish from jumping while I have the canopy proped open and I'm cleaning the glass/vacuuming the sand bed?

 

[blaxsun]

Weigh them down.
Seriously, though - I'd try dimming the lights and doing the maintenance right after feeding so they're less agitated. And another set of eyes to act as a lookout never hurts, either.

 

[kamehameha]

I was kind of figuring it was going to be an adventure in vigilance more than anything. I am not going to have too much in my tank, so if one did go missing, I should notice right fairly quickly.

I also thought, if I made a mesh canopy, I could get some fish netting to attach to the bottom of the lid and the other side to the tank so I could kind of lift it up like a popup net or something. I think that would get in my way more than it would help though lol.

 

[Calm Blue Ocean]

When it looks like my wrasse is in that kind of mood I'll just slide my mesh lid over enough to give me room to work rather than remove it completely. If I need to do more extensive work in the tank I've been known to jam towels between the wall and tank so I might have a shot at catching her (she did jump during cleaning once and of course went straight down between the wall and tank). But mostly we just watch her carefully and if she starts to get that wild look the lid goes back on 'til she settles.

 

[DaddyFish]

Use some clothespins and hook a curled/rolled piece of plastic screen mesh across the back of the tank. If you shape it curled, the jumper will flop right back in the tank.
But mainly, do a fish count every few minutes to make sure you aren't missing anyone. If you're missing someone like a cleaner wrasse, don't immediately panic, just do a thorough perimeter search. It's probably hiding in the sand or rocks.