Filterless Goldfish Tank

[BBradbury]

Hello AA...

Wanted to toss out a "what if" experiment I have going. I have a 55 gallon tank with 12 small Common Goldfish in it and have been removing and replacing roughly half the tank water in it weekly. I have one dual sponge filter in the tank and some basic aquatic plants. I plan to remove a little more water every week until I reach 75 percent. At this point, I'll remove the sponge, replace that with a large air stone and see how the fish do. I'm pretty sure there won't be any difference in the water chemistry, because I'll be removing the water before there's a build up of nitrogen in the water from the dissolving fish waste. With the added aeration from the air stone, the water should be well oxygenated. My thought is, if I remove and replace 75 percent of the water weekly and feed a little every couple of days, there won't be a need for filtration.

Any thoughts good or bad?

B

 

[Mebbid]

My question is "Why?"

What actual benefit to the tank would this pose from making it a relatively unstable tank?

 

[BBradbury]

Hello Meb...

Good question. How would the tank be unstable? From a water chemistry perspective, the water would be extremely clean with a 75 percent water change performed every week.

B

 

[Mebbid]

Thats an assumption. Youre deliberately underfeeding your fish to prevent excessive ammonia build up. Also, ammonia doesnt wait 2 weeks to appear in the tank. Ammonia concentrations start to rise within a day of putting food in the tank.

Filters were specifically created to serve a need to maintain healthy stable tank parameters. Theres a reason we are able to keep all the species of fish we can today, ita the advancement of filter technology to fit that need.

I see absolutely no benefit to removing a filter and doing 75% weekly water changes and risking ammonia spikes compared to just running a filter and doing 75% water changes when you know there arent gonna be ammonia spikes.

 

[King Fisher]

What's your substrate? Depth and type? I think it could work. I did something similar to this once and tested the water daily. I was running two HOB's on a 29g that was established for a couple years. I removed the filter cartridges and just ran the hobs for surface movement for a month. I did 50% weekly water changes as usual. Feed the fish once daily. It didn't change anything in the tank and I got the same outcome as if I ran the HOB's with filter cartridges. I'm guessing I had enough BB in the gravel, which was 3 inches deep, on the decorations, plants and inside the HOBs themselves to sustain the water chemistry in the tank.

 

[Delapool]

Be interested how it goes - been looking at getting a 3ft tank but canister filters and a nice cabinet stand to hide it cost a bit. Maybe a 50% twice weekly??

Idly wondering on the old air powered underground filter now. Either a strong one to stand gravel vacs or do that light stocking.

I change out about 50% water each week, sometimes 75%, sometimes 30% (but dosing ferts). Tbh I just fill tank straight from hose (don’t keep deep water cichlids), but have two heaters that come on straight away.

 

[BBradbury]

Hello...

I've found with my tropical tanks, that if change out enough water and often enough, the water chemistry remained constant and the filters were simply filtering water that was already clean. I've kept Goldfish for a couple of years and since they're heavy waste producers and oxygen users, I've hesitated removing the filters. But, my theory is that large, weekly water changes will remove most of the dissolved waste and what's left will be diluted to a very safe level in all the new, treated tap water. The air stone will maintain a good oxygen level. And, since the tank water is very cool for Goldfish, the O2 level will remain high.

As for feeding, the fish are fed three to four times a week. They forage on the other days and help keep their tank clean. A slightly hungry fish is an active and healthier fish.

I'll keep the forum updated.

B

 

[okapizebra]

IMO, no filter with goldfish just sounds like a disaster to me. If you already have the air line going into the tank for oxygenation, why not just attach it to a sponge filter? I feel as if you will always have ammonia in the tank, despite doing tons of water changes, because goldies are always producing waste. This seems cruel to the fish to me.

 

[BBradbury]

No Filter Tank

IMO, no filter with goldfish just sounds like a disaster to me. If you already have the air line going into the tank for oxygenation, why not just attach it to a sponge filter? I feel as if you will always have ammonia in the tank, despite doing tons of water changes, because goldies are always producing waste. This seems cruel to the fish to me.

Hello ok...

There's no harm done to the fish. In fact, the water is better provided you commit to the 75 percent water change weekly. The filtering device takes in dirty water and returns the water to the tank a little less toxic. The problem with the filtering system, is it can't remove the old, polluted water and replace that with pure. By removing 75 percent weekly, the 25 percent toxic water left in tank is diluted to a very safe level in all the new, treated tap water. The pollutants the fish add between water changes is diluted in all the pure water from the previous water change. The waste is removed before it ever builds up in the water. There's nothing for the filter to do, but move water that's already very clean. So, the filter is removed.

B

 

[BBradbury]

No Filter Goldfish Tank

Thats an assumption. Youre deliberately underfeeding your fish to prevent excessive ammonia build up. Also, ammonia doesnt wait 2 weeks to appear in the tank. Ammonia concentrations start to rise within a day of putting food in the tank.

Filters were specifically created to serve a need to maintain healthy stable tank parameters. Theres a reason we are able to keep all the species of fish we can today, ita the advancement of filter technology to fit that need.

I see absolutely no benefit to removing a filter and doing 75% weekly water changes and risking ammonia spikes compared to just running a filter and doing 75% water changes when you know there arent gonna be ammonia spikes.

Hello Meb...

There's never an ammonia spike because there's too much clean water being put into the tank weekly. The waste the fish produce between water changes is diluted in all the new, treated tap water. The waste water is removed and replaced every week. There's never a build up of toxins.

The fish aren't under fed. They're fed a little every other day. As we know, fish can easily go a couple of weeks without eating. A slightly hungry fish is actively foraging around the tank looking for that bit of uneaten food and is helping keep the tank cleaner, longer.

This system isn't new. It has been around for decades. The filter is simply someone's brilliant idea to aerate the tank water and to provide a little wiggle room for the 20 to 30 percent water change people. I'm simply removing and replacing twice as much water and bypassing the filtration device. In a tank that gets such large, weekly water changes, the filter is simply moving water that's already very clean.

B

 

[rlederer]

The filter does more than just agitate the water for more oxygen, it cleans tiny particulate matter from the water. Sure, removing and replacing water does that too, but a filter is doing it constantly. I change water weekly in my many tanks and still my fine filter pads (100 micron) are dirty and need to be changed weekly as well, so I know that just removing water isn't sufficient to keep the water very clear.

 

[Leeatl]

The filter does more than just agitate the water for more oxygen, it cleans tiny particulate matter from the water. Sure, removing and replacing water does that too, but a filter is doing it constantly. I change water weekly in my many tanks and still my fine filter pads (100 micron) are dirty and need to be changed weekly as well, so I know that just removing water isn't sufficient to keep the water very clear.

 

[BBradbury]

No Filter Goldfish Tank

The filter does more than just agitate the water for more oxygen, it cleans tiny particulate matter from the water. Sure, removing and replacing water does that too, but a filter is doing it constantly. I change water weekly in my many tanks and still my fine filter pads (100 micron) are dirty and need to be changed weekly as well, so I know that just removing water isn't sufficient to keep the water very clear.

rl...

The small particles in the water are constantly dissolving as is everything else in the tank. By simply removing most of the water every week, I can remove whatever has dissolved in it that might make the water hazy. I have some tanks that still have the filters in them and truthfully the water in those tanks isn't any clearer than those without. My point is, if you can commit to large, weekly water changes of at least 75 percent or leave just enough water for the fish to swim in between water changes and don't overfeed your fish, you don't need mechanical filtration. It's hard to imagine changing out this much tank water consistently, but imagine how healthy the fish will be if you can. Of course, only one in 10,000 tank keepers can do it.

B

 

[King Fisher]

I remember hearing stories from old school guys who when they started out in fish keeping as young men only used air stones/under gravel air driven filters. There was no fancy filters or affordable ones at the time. The plastic crate looking things that sat under the gravel was the standard technology. Lol. They changed out large amounts of water weekly to twice weekly. It worked for them. Filter technology definitely provided an easier way of doing things and keeping the tank cleaner by simply cleaning the filter media after it's picked up a lot of the debris in the water column rather than cleaning the tank itself regularly. The media in modern filters provides that buffer with extra BB so the tank can handle bioloads easier. But substrate, plants and decor can provide needed BB accumulation to sustain a tank. I think your idea works because it's already been proven but the technology behind filters nowadays is very convenient and simple which people like [emoji106][emoji106][emoji106]

 

[BBradbury]

Hello King...

I can relate to the "Old School" guys. I'm one of them. Keeping fish healthy is 100 percent about keeping their water nitrogen free. The large, regular water change will do this. I've been in the hobby some time and have never run across a filtering device that can remove and replace tank water. If you find one, please let me know. In the mean time, I'll keep following the most aggressive water change routine possible.

B

 

[rlederer]

I think what you are doing is fine if that's your preference. One comment though regarding the small particles "constantly dissolving" in the water. Dissolved particles become part of a solution, like salt in water. But there are many particles that do not dissolve , like dust from the air and other pieces of debris and waste that will not go into solution. A fine filter will get these.

 

[earhtmother]

Ok have to say something here. I too remember as a teen setting up my first tank with an undergravel filter and plants 45+ years ago. I totally understand the premise of 50/75% weekly WCs and do them when I can but my life is too hectic and unpredictable to commit to doing this. I am a chronic over feeder who is working hard to overcome this issue but without a knowledgeable someone standing over my shoulder when I feed is a VERY hard habit to break. I also can't grow aquarium plants to save my life so I am VERY glad that my HOB is there to CMA[emoji3061]. I only run them with filter floss unless I need to clear a medication out of the water when I'll add carbon. I DO do 50/65% changes as often as I can but I admit its probably more like every 2/3 weeks. Do I wish it was more often YES, do I have fish losses yes again but only when I am particularly negligent about water changes or get lazy and don't quarantine fish from unknown sources (auctions usually)
So BB and Kingfisher some of us are trying to follow your examples but lack your commitment

 

[BBradbury]

Hello again rl...

Water is call the "Great Dissolver". Absolutely everything that's placed into the tank and under the water will eventually break down. It may take months or even much longer, but that's the great thing about water changes. By simply removing the water, you're removing everything that has dissolved in it. Mostly, it's nitrogen from fish waste, but it's also the breaking down of plant material, driftwood, decorations, and whatever else is placed under the water.

B

 

[BBradbury]

Hello mom...

I understand. But, I've made a commitment to my many, many fish and to myself not to slack off on my water changes, ever. Because I keep so many large tanks, this has become an obsession and a real life changer over the years. Needless to say I don't get out much. By diligently changing most of the tank water weekly, I avoid having quarantine problems, new fish go right into the tank. Because, the others are healthy and I've found healthy fish in pure water conditions aren't likely to be infected by anything. I don't have water chemistry issues, I can keep a lot of different aquatic and land plants, I can bypass all mechanical filtration if I care to and never vacuum the bottom material or ever test the tank water. I know the water chemistry is always near nitrogen free. That's a lot of stuff I never have to do, because I'm a water change fanatic.

B

 

[King Fisher]

But fish in the wild deal with a lot of debris in their natural water systems. Rarely are they in Crystal clear waters.

I think what you are doing is fine if that's your preference. One comment though regarding the small particles "constantly dissolving" in the water. Dissolved particles become part of a solution, like salt in water. But there are many particles that do not dissolve , like dust from the air and other pieces of debris and waste that will not go into solution. A fine filter will get these.