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Results 1 to 7 of 7
  1. Default Beginner Stocking 20 gallon

    0 Not allowed!
    I have recently bought my first 20 gallon freshwater aquarium!
    Over the past week of cycling I have added 5 harlequin rasbora and 2 ghost shrimp (I know it may have been a bit much, but under close monitoring and frequent water changes they have been thriving).

    While I am a few weeks off of adding more fishies, I am (not surprisingly, knowing me) anxious to figure out what I am going to add to my tank.

    I have my 5 rasbora, I was also thinking I would like 4 guppy, 3 oto, 2 ghost shrimp and 1 dwarf gourami. BUT.... after first reading that rasbora are schooling and need at least 3, I read that they should be kept in groups of at least 5... and the difference of adding the second two was simply amazing, they are obviously much happier fish. Now I am reading that they should be kept in groups of at least 8.... And the oto cats... I have read anywhere from being ok on their own, to needing at least 3, to bare minimum 4.
    So.... I want what I want, but I will happily pass up my beloved guppies to make the other species I want (rasbora and oto) happy without overstocking my tank. Should I stock 8 rasbora and 4 oto? Would that overstock my tank with the 4 guppy and 1 dwarf gourami?
    If the rasbora and oto are ok in the smaller groups... would adding 2 platy overstock the tank?

    My tank is a 20 gallon TopFin, with the topfin power 20 filter. I have been doing 25%ish changes every 3 days, and intend on doing upwards of 20% every week post-cycling, while keeping up with gravel vacuuming and algae scrubbing (I figure if you're going to do a hobby, you may as well do it right, especially when living things are involved!). It is moderately planted, with a combination of artificial plants and a single java fern and a couple ornaments and river rocks. I may add more live plants when funds are available. I am feeding my rasbora flake food, with supplemental blood worms, and have algae tablets for when I add more fish (and will also provide veggies, when I figure out which ones!).

  2. #2


    0 Not allowed!
    Hello, congratulations for doing your research. You seem to be on the right track. Schooling fish like rasbora should be kept in schools of 6 minimum. Since they aren't very big I'd say that a tank of that size could have a school of up to 10, including guppies, otos and gourami. Many people say that otos are schooling fish. I don't think so based on the observations of my 7 otos. Each does its own thing without caring for the others. I would recommend getting 3 or so just to let them have a few buddies. Guppies in your preferred number and a gourami will fit in too but a dwarf gourami is fairly aggressive despite its small size. Look up honey gouramis and see if you like them. Smaller and very peaceful fish.

    While the tank will be able to accommodate all of these fish by size and space, you likely will have to add some more filtration capacity to that tank in order to have a good water quality. It is recommended to have a filter(or filters) with a total rating for at least double your tank's amount. So for your tank you could have a 40 gallon+ filter or two 20 gallon+ filters. It also would be a good idea to increase your water changes to 50% per week.

  3. Default

    0 Not allowed!
    Research is something I do well... and maybe a little obsessively! :)
    I hadn't considered the honey gourami, although I had heard they were peaceful. I suppose I had assumed that the dwarf were... smaller, based on the name :P I had also heard they weren't typically aggressive. But now I will look at honeys as well, I really do wish to avoid any fishy-homicides.

    Another filter is already on my wish-list, below the guppies and above everything else (I really do have a bit of an irrational love for guppies). I'll probably buy a second 20 gallon filter, as the first one came with the kit I was given. Now at least I have a better idea of how much more filter I need.
    As for water changes... 50% is easily done for me. Is there anything other than chlorine/chloramine I need to look out for when changing water? I am on well water so chlorine is a non-issue, and I do check the temperature of the water I am putting in to avoid shocking the fish... but I do wish to do it right.. so if there are any other hidden hazards, please let me know :P

    After all this research, I will never know how my childhood friend Henry the guppy lived for 3 years in a 1 gallon tank, with no cycling, weekly soapy empties and scrubs, through all the other fish I made him put up with... and no heater (and not a single filter replacement). I always admired that fish, but now I feel as if I haven't given him the appreciation he deserved !

  4. #4


    0 Not allowed!
    Dwarfs grow to 6-7 cm or so, honeys rarely make it to 6 and are much more slender built. For well water you may have issues with other contaminants such as metals. Seachem prime is a good conditioner that removes pretty much every harmful substance known to aquarium keeping from your water. If you really like guppies, have you heard of endler's livebearers yet?

  5. Default

    0 Not allowed!
    You're right, I probably do have metal contaminants... I know the water here is fairly hard, and is softened using salt... I had asked at Petsmart when I picked up my tank but the lady didn't really directly answer my question... she only mentioned that guppies need aquarium salt, nothing else about the contaminants I might find in my water. I've been doing what I do best and just monitoring my rasbora very closely.
    I had tried to find a decisive answer on the debate of adding salt to a FW aquarium... I didn't have much luck. I had decided to go with the middleground and added half the recommended amount of kosher salt, it made a huge difference in the liveliness of the original 3 rasbora.

    I have heard of endler's, but I have never seen them in action (although I also haven't looked too hard). Are there many differences? Guppies are flashy and nostalgic for me, and smaller than the other livebearers I have seen. But endler's at least sound a little more sophisticated than guppies... something my tank is in sore need of!

  6. #6


    0 Not allowed!
    A 20 gallon isn't that big. Harlequin rasbora is any of the three main trigonostigma species. I keep those. 5 is the bare minimum for a group, they need that to establish who's boss. I'd bring this up to 7. You could add a few guppies or endlers to that and a small peaceful gourami. Harlequins are ferocious hunters for anything that wiggles and will really appreciate live food. They will tolerate medium hard water upto ph 8 but if you really want to see them at their best keep 'm in soft water, add some leaf litter and plant cover. Get it right and they can look as good as this on

    And no, I do not use salt.

    With the ottos. Wait until the tank is mature and all grown in before adding those. It's a species that does best in a mature tank with wood and algae but even then will benefit from additional food.

  7. Default

    0 Not allowed!
    Thanks for the input, Talldutchie :)

    I was wondering about the dominance behaviour I was seeing in my rasbora. With only 3 of them it was a lot of chasing, nothing aggressive but there was always one being chased. With 5 of them it is a lot calmer, a lot of "puffing up", vibrating and body checking. It seems to have settled down now. I'll look into getting two or three more, they were not my first choice in fish but I do love seeing them school together and haven't minded having to get more! They aren't quite as bright as the image you posted, but they're looking significantly better over the last few days... so I must be doing something right...
    I will remember the live food thing, I was going to get some for fun but I had noticed they aren't terrifically interested in anything I have given them (other than the dried bloodworms), unless the food is being thrown through the filter-stream.
    I was going to get my otos last, after everything has cycled and settled down, I've heard they were delicate. And as I said before, I wish for as few fishy deaths as possible! I will let some algae build up, and feed them algae tablets and cooked veggies.

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