# Fish for open top tank



## Kronnie (26 Jul 2020)

I have a planted 300ltr tank with 5 x SAE, 5 x Ottos, 13x copper harlequins and quite a few shrimp. I want to add more small shoaling fish but have had issues in the past couple of weeks with fish jumping out of the tank, this appears to be for no good reason. I have lost 1 x SAE and 3 harlequins. The tank is approx 60 days old.
I have good flow rate with two external canisters which pushes the water around well, i am injecting C02 but the drop checker is always green/lime green never yellow.
Any suggestions on fish would be good.

Thanks
Lee


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## Nick72 (26 Jul 2020)

Firstly, your tank is looking great.  Very healthy looking growth everywhere.

Well done.

Some people seem to suggest that fish jump because they are trying to escape less than optimum tank conditions.

I'm sure this is possible, but suspect 95% of fish that jump the tank do it because fish jump.

It's just natural for fish to occasionally jump.  Sometimes they are spooked by other fish, or someone moving past the tank, but on the whole it's just something fish do.

Of course some species are more prone to jumping than others.

Hatchet fish, who spend 90% of their time on the surface are really prone to jumping.

Fast fish, and I count SAE in this, are prone to jump.

Mid-level swimmers and bottom feeders are less likely to jump.

That said Panda Garra jump.  Mines only been in the tank 1 month and has jumped 3 times.  We are lucky to have saved him on each occasion.

IMO if you have a rimmless tank you have to expect the occasional fish to jump.

Oh, and shrimp are forever jumping in my limited experience.

By the way, what is your substrate?


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## Kronnie (26 Jul 2020)

Thanks Nick72.
My substrate is EcoComplete with root tabs. My water parameters all look good, no ammonia or nitrite, Nitrate is within limits. I am doing two 30% water changes a week with one of these being a general trim/tidy up. My water is very hard and PH on the high side but with a good drop once C02 limits are reached.
I kinda put the fish jumping down to bad luck and one of those things in a rimless tank, so far no shrimp have escaped, fingers crossed but a constant battle retrieving them from the filters .


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## Ed Wiser (26 Jul 2020)

All fish jump. The problem is people see pictures of tanks with out lids as the example of what an aquarium looks like. But this an image that is in real in practice. I use mesh screen lids and glass plate lids on my aquariums.


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## mort (26 Jul 2020)

Fish do jump unfortunately and I doubt it's related to water quality. Do you have any idea when they are jumping? Most fish tend to get spooked as the lights shut off and it's wise to stagger this (or slowly dim the lights if possible). When my lights go off in the winter I hear my pencilfish occasionally bang on the glass lid (in summer there is enough ambient light to stop this). I have a mass of floating plants on the waters surface and the tank is heavily (jungle style) planted, and know the fish are happy as they spawn readily, yet still have the jumping.


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## Kronnie (26 Jul 2020)

My lights go off at 8pm whilst i am still about and the room still has the lights on. The fish have been found in the mornings, i think its just a hazard of the tank. Due to the flow i don't think floating plants are an option its also something i don't think i want, hopefully its an isolated occurrence


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## sparkyweasel (26 Jul 2020)

Could you fit a cover, maybe the mesh sort, before you go to bed? And remove it when you are up and viewing the  tank.

It's possible that the fish are encouraged to jump if the CO2 level is too high for them after lights-out, or the oxygen is too low. Either could happen (or both) when the plants are not photosynthesising, ie not using up CO2 or producing O2. If that's the case, running an airstone at night would help.
It may not be for that, or any reason; as others have said, sometimes fish jump.


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