Hi All - basic tank setup question

[carled]

Hi all - new to all this. Just taking step up from goldfish bowls to small tropical set-up. Don't have the time or enthusiasm (yet!) to indulge too much in this hobby, but both my daughters & me are keen fish enthusiasts, spending hours gawping at them in aquariums. The intention is to get a few tetras & a guppy or two in there. Is there also a hardy-ish algae/bottom feeder anyone would recommend to help tidy up the tank a bit?

Have been restricted to a peak aquatics 15" hexagon tank for space reasons and have a fluval1 filter/pump and visi-therm 50w heater, which I've set to 25 deg. C to start with.

The tank isn't huge - takes only 25l, but I want to know how much space to leave at the top? It looks nicest when almost full to the rim, but I'm concerned about oxygen flow. The girl in the shop told me to set up the pump/filter so the nozzle's just under the surface so it helps get oxygen in the water. Then there's the condensation tray straight above that. Now if I have it so the condensation tray touches the surface, then surely there's no fresh oxygen getting in to exchange? However, even if there is a gap there then a) it looks a bit ropey having the water below the rim of the tank and b) the hood is quite tight fitting anyway, so surely not too much air is going to get in to exchange either way?

I'm a bit confused here... can anyone point me in the right direction please?

Ta.

 

[rdd1952]

Hi and welcome to the forum.

I'm afraid you won't be able to put much in a tank that small. That is only about 6 gallons and the general rule of thumb is 1" of adult fish per gallon of water. Since most tetras get to about 2", 3 would be about it. I definitely wouldn't suggest guppies as you will be overrun with fry. Most people use tanks of that size for a single male betta with maybe a shrimp or 2 or a african dwarf frog as company.

As for your equipment, if you decide on a betta, you will need to turn the filter down to it's lowest setting as they don't like much current. That filter is rated at 50 gallon per hour which is turning the tank about 8 times per hour. That is great filtration but may be too much current for a betta. I would also suggest swapping the heater for a 25w. It will be plenty for your tank. The 50w could be too strong and any slight malfunction could raise the temp too much and fry your fish.

 

[carled]

Tetras get to 2"?? Good grief, thought they stayed tiny! OK, sounds like the guppy isn't a great idea then!

What about the gap at the top of the tank then? It really doesn't look that nice with the water level an inch or so below the rim as it has now misted up as well, but I don't want to close the gap if it means I'm not going to get enough oxygen in the water!

 

[rdd1952]

Oxygenization (sp) occurs at the surface so you are looking for surface disturbance. That doesn't have to be a splash, just a ripple will do. Obviously, the more disturbance the more oxygen. If you have live plants though, you don't want too much oxygen as your plants will will not do very well without some CO2. You can fill the tank a little fuller and just keep an eye on the fish. As long as they are swimming normally and look ok, you don't have to worry. Just beware if they start hanging around the top and laboring to breathe. Another option is to aid an airstone to pump air into the water. If you do go that route, beware af buying the cheapest one you can find as they can be very noisy and drive you crazy. I have 4 Rena air pumps. They are more expensive but are dead silent.