# A little help with my first aquarium (21l/5.5g)



## Annica

Hi,

As the title says Im new to this and this is my first aquarium, so I have a few questions I was hoping you guys could help me with.

1. My tank is only 21 l, (or 5.5 g) and I have been searching online to find out if this is enough for a betta male/female and a otto.. Some said no and other said yes (and that i could have like 3 ottos and 1 betta). I was just wondering your take on that? If it helps here is a picture of my tank  (also, i will fill it with water all the way to the top, I was in the middle of changing it when i took the pic)










2. MY plants (dont know what they are called, if you do please tell me  ) have gotten some black spotts on the top of their leaves. are these algae? and if so, will an otto eat these or not? If not, how do I remove them?

Here is a picture of it









3. I have heard that ottos cant have any sort of gravel so I just want to know if this one is ok? also, is this filter ok? Its a Marina, dont remember the model..



















Sorry for all the questions, im a newb and just want to make sure I do this right  Thanks


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## Guest

The good news is, your tank is perfectly big enough for a single Betta; however I would give the Ottocinclus a miss due to their somewhat delicate nature in new aquariums and their sensitivity to fluctuating water conditions (especially a swinging pH level) in small aquariums. Different sources will give different advice, however don't rely on certain forums and Q&A sites such as Yahoo! Answers - the information they provide is notoriously unreliable.

The live plants you have are _Anubias barteri_ var. 'nana'. You need to move this out of the substrate and fix it to hard decor simply because if the rhizome (that is, the base of the plant from where the roots grow out) is covered in substrate the entire plant will start to rot. Suitable hard-decor includes bogwood (this ideally needs soaking for a few weeks to remove excess tannins), sumatran driftwood (again, this will probably need soaking) and rock that doesn't contain any carbonate (e.g. Limestone, which consists of Calcium carbonate) as they'll cause your pH to rise.

Chemically inert rocks that won't alter your pH include granite, slate, onyx and lava rock (also marketed as scorio or volcanic rock). You can also use large beach pebbles; but do carry out a simple acid test on any rocks before putting them in the aquarium. The acid test simply entails pouring a few drops of a weak acid such as vinegar onto the rock surface, if the rock fizzes it's not suitable as it contains carbonate.

You may also want to add some bushy, fast-growing stem plants to fill the space in the background and give the Betta more in the way of suitable retreats. _Hygrophila_ sp. is hardy, fast-growing and is readily available from good pet and aquatic stores.

The black spots on the plants are the result of low CO2 (Carbon dioxide) levels in the aquarium water. As you probably know, all plants need CO2 to photosynthesize. The long term effects of low CO2 coupled with high lighting (which causes the plants to photosynthesize faster and use up any small traces of CO2 that are available) causes the black spots. Whether or not you want to treat this by using CO2 injection is your choice; for a tank of this size regular dosings with a liquid carbon additive coupled with moderate lighting will cause the black spots to disappear in time.

Finally, remember to add a heater as Bettas are a tropical species. You'll need to cycle the filter without fish for a few weeks to allow bacteria to build up in the filter. A liquid test kit is also a wise investment as it will allow you keep a close eye on the water quality.


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