Stocking for a 10 gallon

Hey! I currently have a 10 gallon tank that is my first tank. It is fully cycled and currently has a small goldfish in it. I know that goldfish will grow too large and am planning on finding someone nearby with a pond and giving it away in the future once it grows a little bigger - right now it is about 2.5 inches. Anyway, I've been researching the way I want to stock the tank after the goldfish leaves and was wondering if I could get some input on some of my ideas. First the water parameters are:

• pH = about 8.2 out of the tap, but I've been using Seachem neutral regulator to bring it down slowly. Right now it is at about 7.8 and my goal is around 7.5.
• Water hardness/alkalinity = pretty hard. According to the Tetra easy test strips, it is around 200 ppm (GH) and the alkalinity (KH) tests around 180 or so
• Temperature = I have a heater so I can bump the temperature up later. Right now I keep it right around 68-70 for the goldfish
• Ammonia and Nitrite near/at 0 weekly and nitrate usually around 5ppm for plants (I dose a little Easy Green fertilizer each week)

With that aside, one of the fish I would really like to have is the Otocinclus catfish. I know that they need to be kept in schools so I was planning maybe 4-5. However, I would also like the ability to have a couple other fish that are not bottom dwellers to add some variety. I was originally thinking of another schooling nano fish like a few ember tetras or green kubotai but have been considering the possibility of doing 2-3 other fish instead. One that interests me is the Scarlet Badis; however, I know that they can be difficult sometimes so I was hoping for some feedback on a tank with 4-5 Otos and 2-3 Scarlet Badis. If not Scarlet Badis, what other recommendations for similar fish are there? Thanks for reading!

Pic of the tank below for any other feedback. Currently a little brown still because of the Mopani which I introduced about a month ago.

All the fish you named are really cool little fish, BUT, sadly they are all soft water fish. I have no expereience with hardwater fish but I do is that if soft water fish are kept in hard water, it will lead to kidney failure... I know guppies are hardwater fish that do well in a 10 gallon... As for hardwater stocking, I cant help much.

The GH (hardness) is of more significance than the pH though that is important too. But the use of pH regulators is not good long-term, and you would be better to deal with the GH (and KH) and the pH will adjust depending. Soft water fish kept in hard water have issues, primary one being the calcium in the water which gets inside the fish and blocks the kidneys so the fish dies.

There are hardwater fish, Endlers Livebearers come to mind, suited for a small tank. There are some cyprinids that could work too.

Lowering the GH/KH/pH can be done by diluting the tap water with some form of pure water. RO (reverse osmosis), distilled, or sometimes rainwater can be used. Keep in mind that this means preparing all water for water changes in a container outside the aquarium, then using that water for the water changes. This is not overly onerous with a 10g tank, as you would be preparing roughly 5 or 6 gallons each week. You could also use just RO, without any tap water. Many soft water species occur in water with zero GH/KH and an acidic pH. And this eliminates mixing to exact balances every time.

Thanks for both of your insight. Water hardness has been one of those things that I haven't yet figured out was super important or not, since I feel like you here different things from different people so I appreciate that you gave a more solid reason as to why it should be considered.

Lowering the GH/KH/pH can be done by diluting the tap water with some form of pure water. RO (reverse osmosis), distilled, or sometimes rainwater can be used. Keep in mind that this means preparing all water for water changes in a container outside the aquarium, then using that water for the water changes. This is not overly onerous with a 10g tank, as you would be preparing roughly 5 or 6 gallons each week.

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I have thought about doing this in the past. If I were to do this, as I already prepare my water (adding seachem prime, etc.) in a separate bucket anyway, would that be a good long-term solution and allow me to keep the fish I mentioned? Probably looking at just getting distilled water to mix with the tap to a softer solution. Part of the reason I am more interested in this is that I haven't yet found a lot of hard water small fish I'm super interested in.

So assuming that I can successfully soften my water, is the stocking above (otos and badis) a suitable stock for the tank? Or should I look at other options? Any recommendations for hard water fish to check out would also be appreciated!

machinemonkey said:

Thanks for both of your insight. Water hardness has been one of those things that I haven't yet figured out was super important or not, since I feel like you here different things from different people so I appreciate that you gave a more solid reason as to why it should be considered.


I have thought about doing this in the past. If I were to do this, as I already prepare my water (adding seachem prime, etc.) in a separate bucket anyway, would that be a good long-term solution and allow me to keep the fish I mentioned? Probably looking at just getting distilled water to mix with the tap to a softer solution. Part of the reason I am more interested in this is that I haven't yet found a lot of hard water small fish I'm super interested in.

So assuming that I can successfully soften my water, is the stocking above (otos and badis) a suitable stock for the tank? Or should I look at other options? Any recommendations for hard water fish to check out would also be appreciated!

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Both otos and scarlet badis would be best in very soft water, so I would suggest considering straight RO. The other issue with the badis is feeding. Twice I had this fish, and both times it did not last long (a few months), I am certain because of food. The second attempt lasted the longest when I fed frozen bloodworms, but it would not eat anything else, and this is not a good staple food. Some members have reported past success with other foods, but this may be luck.

Byron said:

Both otos and scarlet badis would be best in very soft water, so I would suggest considering straight RO. The other issue with the badis is feeding. Twice I had this fish, and both times it did not last long (a few months), I am certain because of food. The second attempt lasted the longest when I fed frozen bloodworms, but it would not eat anything else, and this is not a good staple food. Some members have reported past success with other foods, but this may be luck.

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Ok. Yeah that's definitely something that I had heard before about them and one of the reasons I have been a little hesitant about the badis, outside water parameters. One thing I was also worried about was whether having 2-3 in a 10 gallon with otos would work just in terms of compatibility?

But besides badis, what other similar fish might be good? I'm looking for something that could be ideally kept in a group of 2-3 and that have some color. I was thinking dwarf or honey gouramis but know that they do better alone. Would a male and 2 females work? Besides that, what else.

All of this assuming I decide it's worth going with softer water. Still looking for recommendations for hard water nano fish. I know about guppies, endlers, other livebearers, snails but was wondering what else there might be. Thanks for all the help so far!

Based on what others have said I agree with the water parameters not being ideal for those fish. I would look into multiple Corydoras Catfish. They are very active and come in an array of colors due to there being many different species. They do not get large and have a fairly long lifespan. In my experience, they are hardy fish that can typically handle similar hard water conditions.

There is one fish you may like that I THINK can do well in hardwater... They are pea puffers. Super cool fish that are fairly uncommon... Just an idea. This would come with its downsides though... If you do a pea puffer, they should be kept in a species only tank, because they will take nice size chunks out of other fish... Males cannot be kept together as they will also kill eachother. You can do a male and two females in a densely planted ten gallon tank. I would add in tall plants such as java ferns or Amazon swords... There is also one other downside I for got to mention... They really like to eat snails... So provide a good supply of pest snails so they can eat 2-3 a day. They like the shell to keep their teeth filed back... I'm thinking of getting one after I'm done using my ten gallon as a QT tank for my 20g which has a ton of pest snails I can feed the puffer...