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125G Dirt Goldfish Tank - My First Freshwater

2203 Views 7 Replies 4 Participants Last post by  Andrew Goldfish
For 23 years I maintained a saltwater aquarium filled with "Rambo fish" like triggers, lionfish, puffers, damsels and clownfish. I finally decided to pack up my salties to the local Petco and convert to freshwater. After doing a lot of research I decided to turn my 125 gallon tank into the type of habitat that 4 Oranda goldfish would pick if they had a vote.

After years of using buckets to do saltwater water changes I finally got a siphon for the sink. Bye bye saltwater.

The background that I'd been using for 20 years had a freshwater scene on the other side. How convenient. Printed in Japan. Penn- Plax. 1987!

After a thorough vinegar tank cleaning I added 1 inch of organic potting soil and covered that with 1 to 1 1/2 inches of medium to large smooth gravel. The local Lowes didn't have the popular Miracle Grow in organic so I got another brand that had the same stats.

Next I added a wide variety of plants in the back as the tank cycled to see what type would grow best in my setup. I was well aware of the potential problems of goldfish uprooting and eating/killing your plants and making a muddy mess. But that won't be considered a problem, since the driving theme of this tank is to make an ideal habitat for the goldfish.

The test plants were Anubias, Java Fern, Green Crypt, Crypt Balanse, Bacopa, Amazon Sword, Umbrella, Ludwigia, Wisteria and Peacock Fern. I basically got every type from my local Petsmart and Petco that someone said did well with Goldfish, plus a few others that I liked the look of.

I added a double light strip to increase plant growth and got rid of the aquarium's glass lid. Aqueon 36 inch: 6700k daylight and Colormax bulbs. I'm not going for crazy levels of light, but I figured the plants would need more than the Lowes GE daylights I used for viewing my saltwater fish. 30 watts * 2 + 21 watts * 4 = 144 watts for a 120 gallon tank. The plan is to run them 6 or 7 hours a day and see how fast the plants and algae grows.

I kept the same 3 box filters on the back, rated for around 180 gallons of water. It's probably more aeration than the plants would like, but I'm hoping to grow four healthy Orandas to their full size so I figured even with the plants I'd eventually need it. I didn't put any carbon in the new filters.

The plan is to let the tank cycle for a month or so with just the plants and see how it goes. Then maybe add a few plant friendly fish for maybe another month while doing weekly water changes of about 20 percent.

As to why I decided to keep Orandas: I went through the list of breeds of fancy goldfish and watched YouTube videos to see what types I found interesting to watch over time. Orandas seemed the most intriguing to me.

So the long term plan is to have four Orandas in a heavily planted tank with some small driftwood and maybe a few other small structures. The stretch goal being to actually breed the fish.

So that is where I stand one week later. I got three Mopani pieces of driftwood that I boiled and will be soaking for a few weeks. Right now I don't think I want any big structures other than the plants so the fish have maximum swim area.

But this is ALL completely new to me, and everything I've done so far is based on researching some forums, websites and YouTube channels the last two weeks. Any and all advice welcome. Oh and I also just got Walstad's book.


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Pretty cool setup. I'll be interested to see how it goes once you add in the orandas. I have always loved goldfish but have never really had a setup specifically for them.
I'm intrigued by the idea of a planted goldfish tank. I'm glad you've done your research and are already aware of the potential problems. 125g is an awesome size for a GF tank, and orandas are so beautiful and fascinating to watch.

Btw ... what temperature are you keeping the tank? I ask because goldfish are cold-water fish but your plant list appears to be all tropicals, so I assume they need a heated tank? Since you're experimenting, maybe look for plants that will do well in an unheated tank.
Thanks for the comments. The tank will just be at room temp, between 69 and 77.

And here's a small update.

After boiling my Mopani driftwood pieces and soaking them for a few days they finally seemed to stop leaching tannins into the bucket. So I tried my hand at attaching my Java Fern with brown thread to two of the pieces. So at least there is a little structure in the tank now instead of the boring test row of plants.

And now the hard part: doing nothing with the fishless tank for a week.


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Hey everyone. Well I started this tank journal here and at Koko's Goldfish forum. Since I got way more responses over there, including from some people whose YouTube videos on Orandas I watched (small world!) I think I'll do the weekly updates just there and keep this journal for plant specific questions.

After 20 days things seem to be going well. Lots of green plants and so far no trace of algae.

Here's the first video I tried making.
If you throw some Purigen in your filter it'll pull the tannins out of your tank water. Nice thing about Purigen is it turns dark to let you know when it needs to be recharged. Recharge it and then re-use, unlike carbon. You'll probably need to recharge it pretty frequently at first, till the logs slow down with the tannin leaching.

With as low lighting as you have on this tank, you probably need to stay on top of the tannins to make sure as much light as possible gets to the plants.

What other plants are you planning on trying?
I did a water change that seemed to get rid of the tannins. I got lots of plants to see what will grow well in my setup. Swords, java fern, anubias, bacopa, wisteria, crypts, vals, and now duckweed, water lettuce, water sprite and hornwort. Looks like a green lava lamp on the surface.

I changed the lighting schedule to 5 hours in the morning, off for 4 hours in the afternoon, and on for 5 more hours in the evening for a 14 hour day cycle.


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Four years later... hey everyone! I made a video going over the four year history of this dirt planted goldfish tank. I couldn't figure out how to embed it in this post so for now I'll just leave it as a link. There have been some major changes since this video and we are thinking about trying to give breeding ranchus a try.
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