(lots of) General questions before I set up new tank

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Nov 22, 2020
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Hi all! Got a tank from my friend to fish-sit for a year or two, and we want to make some changes. Basically, we’re gonna upgrade from a 10 gallon to a 20 gallon tank. Below I have a list of current setup, changes I’m planning on making to the setup, a list of questions, and some photos at the bottom. Feel free to answer/comment on whatever you want, I understand it’s a pretty big list lol. Excited for another tank project!

Current Hardware
  1. 10 gallon tank
  2. Sponge filter
  3. Undergravel filter (turned off currently)
  4. Lid
  5. Light
Intended Hardware Changes
  1. 20 gallon tank (¾ full because of college policy (though I don’t think my RA is super well versed in what a 15 gallon tank looks like, so I might fill it all the way))
  2. Aquaclear 50 w/ aquaclear biomax pouch, foam thing, and marineland activated carbon in non-name-brand pouches
  3. 100 watt aquatop heater
  4. Different light
Current Plants
  1. 3 bamboo
  2. 1 amazon sword roots wrapped in java moss
  3. 1 red rubin (?) sword roots wrapped in java moss
  4. 1 vallisneria (nana?)
  5. 2 random small plants attached to rocks
  6. Java moss
  7. Random floating bits of plants
Intended Plant Additions
  1. Vallisneria gigantea
  2. cryptocorynes
Current Hardscape
  1. Black sand
  2. 1 piece of driftwood
  3. (1 piece that is not currently in the tank for space reasons)
Intended hardscape additions
  1. The other piece of driftwood
  2. More black sand
  3. Pile of small to medium river stones I got from a river (see question 8)
  4. Plastic pots (see question 2)
  5. Dirt from a field/prairie (see question 2)
Fish (don’t think I need to add more)
  1. 2 bristlenose plecos (Ham and Cheese)
  2. 1 honey gourami (Phoebe)
  3. 1 ranchu goldfish (Veronica (Ronnie for short))
Current Routine
  1. 50-75% water change weekly & rinsing filter
  2. ~25 Aqueon goldfish granules for Ronnie in the evening
  3. small/medium pinch of Aqueon tropical flakes for Phoebe in the evening
  4. 1 cube of frozen bloodworms 1-2x weekly
Intended Routine Changes
  1. 25-50% water change weekly & rinsing filter (see question 10)


  1. Any extra plant suggestions that plecos and goldfish won’t eat?
  2. Plan rn for plants is to free all their roots and plant them in soil that I’m planning on digging up from a prairie/field in the back of the tank in a bunch of square plastic nursery plant pots all hot glued together into a sort-of trough. Pots will also be scattered around the rock pile. Will the soil be an issue for the tank at all? Will the pots leach anything into the water? Here’s a link to an example pot: https://www.amazon.com/Plastic-Nurs...efix=small+square+nursery+pots,aps,116&sr=8-2
  3. Should I feed the plecos anything? My friend’s had them for around a year now, and they’re still alive and active, though they’re smaller than I think they should be at that age (2 inches) (I used to breed Bristlenose Plecos, and they grew about a quarter inch per month). Or are they stunted because of the tank size?
  4. There is a non-adjustable heater in the 10 gallon right now. In the 20 gallon, should I use just my 100W aquatop heater or should I use both in tandem? I’m scared the 100W won’t be enough.
  5. If I put the new filter in the 10 gallon and run it for 2 or 3 weeks alongside the current filter, then transfer everything in that tank to the new one, will I need to cycle anything?
  6. I’m like 50% sure the 20 gallon, which I got used, had a small amount of kitty litter on the inside probably from it just getting kicked up into there from the litter box. I vacuumed it, then filled it up with water, then scrubbed the glass with a paper towel, then emptied it, then filled it again, then emptied it. Would that be enough to make the tank safe?
  7. While leak testing the fish tank it was under the towel rack in the bathroom, so it inevitably got some suds in there from hand washing. I emptied it out, should I do another extra wipe down or should it be fine?
  8. Do I need to do anything with the rocks I got from the river downtown? So far I’m just planning on pouring boiling water over them to sanitize them and rubbing the mud off, though I heard they can mess with water parameters…
  9. Do I need to test the heater? It turns on. If so how should I test it? Could I test it in a 5 gal bucket?
  10. Should I change to a water change every other week in the 20 gallon?
Nice Goldie
My goldfish will have a nibble of everything apart from dwarf hornwort Lillie's and swords.

I wouldn't use dirt, if the plants start to lack nutrients like that sword or echinodorus? You might need to use root tabs and that will be messy.
Pleco should be fed, it could be stunted or maybe a runt.
Do you actually need a heater? My tropical fish tanks are set to 22°c and can fluctuate up to 24°c when lights come on, they do drop down to 22 during our frosty mornings though.
Put old folder media in new filter watch for mini cycle.
Leave the new tank to dry out for a week, that will kill most aquatic bourne nasties.
All river rocks I've tried have been fine, my guess is if they're in a river they will be water safe. Obviously don't use if there's masses of oil leaking from up river. Boiling will kill everything.
Change water when it needs changing, keep nitrates below 50ppm. The more you feed the more nitrates are created
Everyone is going to give you a hard time about the gourami and goldfish together, in particular about water chemistry and tank size, but also temperament. Don't worry about it. If they have been together that long, leave them together.

Ideally the goldfish would have medium hard water and the gourami soft water but goldfish can live in soft water too.

Goldfish can get big (10-12 inches without the tail) and need space to move but yours is a ranchu and they don't swim fast or far. In a few years if you want a bigger tank, get a 4 or 6 foot tank for it, but don't worry about it currently. Just move them into the 20 and let them be.


Use can use the same light and filter that you currently have. there's no need to change them unless you really want to. Then I would run the old filter and the new filter together for a few months before removing the old one. But I wouldn't bother with a new filter unless you hate the noise of the air pump.

AquaClear HOB filters come with ceramic beads, sponge and carbon. You don't need to buy name brand or even use the carbon. I just ran 3 sponges in my AquaClears.


Get some 1 inch thick sheets of polystyrene foam to tape to the outside on the base back and sides of the tank. This will insulate it and save a bit of power.


Giant Vallis doesn't do well in aquariums. Stay with narrow vallis.

Cryptocorynes, Ambulia and Duckweed would also work. The goldfish would enjoy the Duckweed and that would help its dietary requirements.


Intended hardscape additions
  1. The other piece of driftwood
  2. More black sand
  3. Pile of small to medium river stones I got from a river (see question 8)
  4. Plastic pots (see question 2)
  5. Dirt from a field/prairie (see question 2)
You don't need more driftwood.

River stones will make it harder to clean and won't help the goldfish, that prefer open tanks with plants along the back and a clear area in the middle to swim and grub about.

No dirt in aquariums. Just use what you have and move it into the new tank. Add a bit more gravel if you need it. Leave it at that.

Don't use soil for aquatic plants or in aquariums, just stay with gravel and use a liquid aquarium plant fertiliser. If you want to grow plants in pots, see below.

If you grow all the plants in pots, you only need a thin layer of substrate so won't need to buy more. the stuff you have should be ample to cover the base of the new tank.

We use to grow some plants (usually swords, crypts, Aponogetons and water lilies) in 1 or 2 litre plastic icecream containers. You put an inch of gravel in the bottom of the container, then spread a thin layer of granulated garden fertiliser over the gravel. Put a 1/4inch (6mm) thick layer of red/ orange clay over the fertiliser. Dry the clay first and crush it into a powder. Then cover that with more gravel.

You put the plants in the gravel and as they grow, their roots hit the clay and fertiliser and they take off and go nuts. The clay stops the fertiliser leaching into the water.

You can smear silicon on the outside of the buckets and stick gravel or sand to them so it is less conspicuous. Or you can let algae grow on them and the containers turn green.


I would add frozen brineshrimp and daphnia to the goldfish's diet. And it needs plant matter like Duckweed or other soft leaf aquatic plants. You can grow a lot of plants outdoors in plastic containers and bring them in for the fish to eat. If the plants are in pots you can move the pot into the tank for a week then put it back outside to recover and grow new leaves.

You can do a similar thing with smooth rocks or plastic ornaments. Put them in a container of water outside until they are covered in green algae. Then move them into the tank for a week so the algae eaters can eat the algae. then put the rocks back outside in the bucket of water to grow more algae.


Kitty litter is fine and just rinsing the tank out with tap water should remove it and any soap suds.

Water changes should be done weekly. Do a 75% water change and gravel clean the substrate once a week.
Thank you so much! Incredibly helpful. I probably wouldn't have done the goldfish/gourami combo either but you get what you get! They're both really fun to watch. And I'd say they get along swimmingly! Changing the light since the facebook marketplace guy gave me a bigger one for free that fit the 20 + a heater, and switching the filter because the sponge doesn't catch any of the gunk, and there's constantly poop floating around lol. And I already have 2 extra pieces of driftwood just sitting around and some extra sand, was thinking of chucking those in there just for the fun of it. And you're right about the river stones, might just scatter them around instead then for the aesthetic look and hide the pots with them. I'll talk to my friend about getting different types of frozen food, I reckon the fish store in town would have some. I'll also see if I can set up the 2.5 gallon she left me to grow some duckweed; dorm life isn't exactly conducive to growing plants in buckets outside lol. Again, thank you!!
I see you’ve gotten a lot of advice already, but here are some extra tips.
  1. Not sure
  2. I wouldn’t dig dirt up from fields or anything, because dangerous microscopic things can live in the dirt, and leach diseases into the aquarium.
  3. You should feed the plecos sinking algae wafers or the like sinking wafers. Goldfish love food and most likely will not leave any for the plecos.
  4. I have a Fluval 200wt for my 20 gallon long. Just turn it on a lower wattage, or get a 150wt.
  5. It depends on how much beneficial bacteria happens to lock onto the new filter. Most likely, you will not have to do much of a cycle, with cycled sand and a cycled filter, however, I would run it for a few days before adding fish, to ensure stability.
  6. I’m not exactly sire if it would be safe now, but maybe try and use some white vinegar to water mix and clean it to be sure.
  7. Again, I would scrub it out with vinegar.
  8. There is always a risk with using rocks from the wild. There is a method to test whether they’re safe or not, something to do with different chemicals, but I don’t remember what it is as of now.
  9. You don’t need to test it first as long as you don’t put the fish in for a few days.
  10. Still do weekly water changes. Goldfish are very messy, and put out lots of waste. Even I 20 gallon is relatively small for a goldfish, so just make sure you never miss water changes. Also, with all the different foods you have to feed the fish, you may want to do 30-40% water changes weekly.
Note: never change the water and the filter on the same day.
2nd Note: as others have said, you may not even need a heater.
Hello. Three things for a successful tank. Water change, water change and the most important: Water change. Do this simple task and your fish will be fine.

10 Tanks (Now 11)

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