20 gallon stocking question

[Otocinclus dude]

I’m thinking of getting a 20 gallon tank but I don’t know if it is ok
Here is what I am planning on putting in it With a Top Fin Power Filter 20 and the dimensions of the tank are 24 in L x 12 in W x 16 in H
8 Galaxy Rasboras
3 otocinclus (already have these in a 2 gallon)
1 dwarf gourami
1 velvet wag swordtail

AqAdviser.com says it is at 87%
Temperature range 73.4 - 75.2
pH range 6 - 7.8
Hardness range 5 - 15 dH

Thanks in Advance

 

[Colin_T]

Hi and welcome to the forum

No to the gourami and swordtail.

Dwarf gouramis (Colisa lalius) and all their colour varieties are regularly infected with the Iridovirus and Fish Tuberculosis (TB). You should avoid these fish at all costs because once those diseases get in your tank, you can't get rid of them unless you disinfect everything with bleach.

There are plenty of small gouramis that are normally free of these diseases and would be fine in the tank. Licorice, Honey, Indian Banded gouramis are some examples.

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Swordtails come from hard water with a pH above 7.0. the other fishes you listed come from soft water. It is preferably to only keep fish that are suited to your water chemistry (GH and pH). If you have soft water, then keep the fish you listed without the swordtail. If you have hard water, then keep livebearers like swordtails, platies, guppies.

What is the GH (general hardness), KH (carbonate hardness) and pH of your water supply?
This information can usually be obtained from your water supply company's website or by telephoning them. If they can't help you, take a glass full of tap water to the local pet shop and get them to test it for you. Write the results down (in numbers) when they do the tests. And ask them what the results are in (eg: ppm, dGH, or something else).

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Regarding the filter, TopFin aren't the best filter around due to their filter pads/ cartridges. A better brand of filter is the AquaClear hang on back (HOB) style filter. They look similar to the TopFin but re much more user friendly and have better filter media that doesn't need replacing. Unlike the TopFIn, which the company wants you to keep buying filter cartridges.

AquaClear HOB filters cost a bit more but are in my opinion, a much better filter to go for.

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Regarding tank size, if you have room for a bigger tank, then go as big as you can afford to buy and have room for, but don't get too carried away. The tank you have listed (24x12x16) is fine for a few small fish, but bigger tanks allow you to have more variety, and if you want some bigger fish, then a bigger tank is better for them. However, if you only have space for that tank, or have limited finances, then get it.

 

[Otocinclus dude]

I had looked into licorice gouramis but most articles I read about them said they are very hard to keep alive because of the strict pH, dH, and temperature


I haven’t got the tank and I have based most of stocking on AqAdviser Thank you for the advice about the filter I think a 20 gallon is the biggest I can go but I might be able to go a little say in the 20s range

 

[Essjay]

One problem with stocking calculators like AqAdvisor is that they only take the size of the fish into account. They cannot be programmed with all the variables we need to consider, such as GH requirements as Colin mentioned. They also cannot tell the user about which filter is better than which, and why.

 

[seangee]

What is the hardness in your tank?
Galaxy rasbora (aka celestial pearl danio or CPD) really need to be in a larger group. These are quite timid and shy, so to be able to see them you need a good size group in a well planted tank, they will come out more if there are plently of hiding places. They also don't cope well with active fish that will out compete them for food. They really are better off in a species only tank - but otos are fine.

Otos are also sociable fish and should be in a bigger group. These do not cope well in "new" tanks as they feed continuously and need the tank to establish a decent biofilm to graze on. Assuming the hardness is ok I would start with 20 galaxy rasbora. Once the tank has been established for a month or so add another 6 otos. I would not add any other fish if you want to keep the galaxy rasboras.

If you feel the need for a bit more variety you could add a small group of cherry shrimp. No need to worry about numbers here as it will turn into a large group all by itself .

Forgot to mention: I'm not familiar with the topfin but CPD do not like a high flow. They are also very small and love wriggling into gaps, so make sure there is no way they can get into the filter.

 

[Otocinclus dude]

As I have said before I do not have this tank I am just asking in advance
Wold it be ok if I drop the dwarf gourami and swordtail and keep 6 otocinclus, 1 honey gourami, and 18 Galaxy Rasbora

 

[Essjay]

We need to know the GH of your tap water before we can say yes or no.

 

[Otocinclus dude]

I do not know the GH of my tap water

 

[Essjay]

Look on your water provider's website to see if they give something called hardness. If they don't, phone them to ask or take a sample of your tap water to a fish store and ask them to test for GH.

Whichever you do, get a number and the unit of measurement. Words can be vague and misleading.