Why are tops of aquariums open?

[olavvk]

Hi!
So im new in the hobby and have a glass plate on my aquarium now.

my question is: why are a lot of aquariums with open top? Is this not a big risk for the fish to jump out? And what are the advantages of a open tank?

 

[FishyFishFish]

I believe that open tops improve gas exchange. The other reason is that it can help dissipate heat.

However, I think the main reason is aesthetics.

 

[J1a]

Hi!
So im new in the hobby and have a glass plate on my aquarium now.

my question is: why are a lot of aquariums with open top? Is this not a big risk for the fish to jump out? And what are the advantages of a open tank?

Firstly the gas exchange at the surface of the water is a good way to ensure there are sufficient oxygen in the water.

Secondly, condensation on the glass plate can reduce the light penetration into the tank.

A screen top is just as effective, and avoid all these problems. Not to mention it's lighter to remove for tank maintenance.

 

[tharbin]

Glass lids are much more popular with freshwater. Saltwater tanks hold less oxygen so you need as much gas exchange area as possible. The single largest air/water interface in your aquarium is almost always the tank's surface so you keep it open to improve gas exchange. It does also allow more light penetration and we usually need to get as much light into the tank as possible. It also increases evaporation which can be helpful in warmer climates.

That said, the increased evaporation means you top off more often.

I think most reefers do have tops, usually mesh, because fish do jump but they are often removed during photography.

 

[Randy Holmes-Farley]

FWIW, CO2 is harder to exchange and equilibrate than is O2, and the simple fact that reef tanks often have a pH change day to night is proof that gas exchange is not complete, even with open tops and skimmers.

 

[tracemccune]

FWIW, CO2 is harder to exchange and equilibrate than is O2, and the simple fact that reef tanks often have a pH change day to night is proof that gas exchange is not complete, even with open tops and skimmers.

Good info on both open and closed tops having pH swings. I often hear people say that glass covers hinder gas exchange and am curious whether covering the top makes a noticeable difference.

Do you have a position on whether glass tops appreciably hinder O2 exchange, and/or whether they lead to higher levels of CO2 compared to an open top?

 

[Jedi1199]

I personally removed my glass top for better light penetration.

 

[moz71]

I did try a glass top on a small tank for awhile it did help evaporation BUT what drove me insane was keeping it clean. SALT creep would get so thick so if planning on any corals you will lose large portion of your light. Of course in addition to gas exchange most importantly

 

[Randy Holmes-Farley]

Good info on both open and closed tops having pH swings. I often hear people say that glass covers hinder gas exchange and am curious whether covering the top makes a noticeable difference.

Do you have a position on whether glass tops appreciably hinder O2 exchange, and/or whether they lead to higher levels of CO2 compared to an open top?

I cannot see how it doesn't hinder gas exchange unless you blow fresh air under the top (or suck out the old air), but how much effect it has depends on what other aeration the system has.

The simple fact that fresh (outside) air to a skimmer inlet often does not make the tank stabilize at a pH equivalent to full outside aeration demonstrates that the tank top (or other parts of the system) are aerating significantly.

 

[A;exr54]

my glass top that came with my tank was removed because it was always clouding up my lights. Also trapping heat inside. Plus i have a cooling fan blowing directly on the water surface, that would not work with a glass top on.
I use a screen top and its been great.

 

[thomas flower]

There are lots of advantages to the closed fish tank. Such as Preventing unwanted items from entering the tank, fish jumping out of the tank, Preventing water splashing, Keeps your others pets away from the tank.

As compared to a closed fish tank many more advantages to an open fish tank. At first less cost compared to the closed-on, Look very beautiful, Hassle-free maintenance, Adds another dimension, Easy gas exchange, easy filtering process, it can help dissipate Temperature.

For all the advantages a lot of aquariums use with open-top?

 

[Jeff-Ft-Lauderdale]

Hi!
So im new in the hobby and have a glass plate on my aquarium now.

my question is: why are a lot of aquariums with open top? Is this not a big risk for the fish to jump out? And what are the advantages of a open tank?

I am new too. I always thought it was mostly aesthetics...because it does look cool. But a lot of the reasons listed here make sense. Especially gas exchange...though I always though overflow filters were far more effective at gas exchange than the water surface in the main tank. But you can never really have too much.

Not all fish jump too. I know Clowns do though, and for sure Firefish. I've been pretty paranoid about that.

 

[717_Reefer]

Hi!
So im new in the hobby and have a glass plate on my aquarium now.

my question is: why are a lot of aquariums with open top? Is this not a big risk for the fish to jump out? And what are the advantages of a open tank?

I run my aquariums topless to improve the exchange of co2 but when it comes to saltwater i run a mesh top to keep them from jumping out while still keeping my proper gas exchange

 

[Drummingbaker2010]

Hi!
So im new in the hobby and have a glass plate on my aquarium now.

my question is: why are a lot of aquariums with open top? Is this not a big risk for the fish to jump out? And what are the advantages of a open tank?

yes there is a little risk of fish jumping out, but it also serves as a way to get oxygen into the tank, as well as other necessary gas to enter and exit the tank. If you want to close it, you can add a power head or 2 and have them cycle oxygen and other gasses at the top surface of the tank.

 

[tharbin]

Do not underestimate the possibility of a fish jumping. They almost all can. It will only take one or two loses of favorite fish to convince you. Most photos of open top tanks you see probably have tops that are removed for photos. Many of us use mesh screen tops so the tank is still 'open' but the fish stay in. Kind of the best of both worlds. The downside? More evaporation to replace.

 

[DeniseAndy]

As all others have said We do have tops on them, just not glass. Mesh is how we keep fish in. Trust me. Fish jump!