Tetra glow with goldfish. Will they survive?

Hey guys. I have a well-maintained 110lt aquarium for 2 years now. I have 2 goldfish and 2 algae eaters.
Temperature is all-year round at 24-25. I have both a Juwel filter and an Eheim classic 2217. both full of biological material. So, it is quite ok.
Now, some will be upset, but I have to ask.
Today, I have gone to the store to buy food and bacteria, and my kid saw the glow displayed there. So asked the expert and he suggested to buy up to 4, without any problem. I bought 2. Afterwards, I have started reading that glow doesn't mix with goldfish, they need warmer water etc. And I ve started thinking. Will they be OK?
I have a 30lt aquarium that I haven't used for like 15 years, but it's quite dirty (it was stored in the basement and it has even soil and stones. Neither I have an idea how to clean it, and most importantly, I will have a big difficulty placing it! So, again, I have to ask if they are going to be OK in the 110lt aquarium. If so, I will leave them in.
They have been inside the tank since this morning. Other fishes didn't react, they are accepting them. But they are really small. And one of them seems to let itself to the filter grid. It can leave though, it does leave, goes behind a stone, then goes around etc.
Please don't be too hard on me, I would appreciate any advice..

A whole group of fish have been genetically modified with glow genes. So question one is which glo-fish did you buy?

Thanks so, SO much for the quick reply! IF the expert there is right, I 've bought tetra's.

I really don’t want to touch this one, but for some reason, I can’t help myself… in nature, it probably couldn’t happen… but… glo fish aren’t natural, and typically the one you pictured are made from white skirt tetras, which are a warm water fish, but, are fairly durable…
Gold fish are naturally, typically a cool water fish, but they are also pretty durable, and there are so many of them unknowingly put in tropical tanks, mostly by newbies, and many still thrive…

I would guess you could split the difference on the temperature, and they may survive I wouldn’t do it, but I’ve seen tanks, with an angel fish, and a gold fish both in there and surviving ( I’m using the word surviving, in place of thriving )… the other issue is the adult size difference between a gold fish, and the tetras

Your tank is warm, and that type of glofish is big enough not to become food. In general, goldfish kept that warm don't do as company for one very good reason.

Poop.

Goldfish are herbivores with an inefficient digestive system. They aren't as bad as koi, but they produce a lot of very rich waste, which they can tolerate to a point. They can be a lot of work to keep clean, as you know by now. Most tetras can't tolerate poop in the water. The original danio glofish were developed for use in water treatment plants, as their colours reacted to water pollution. They light up in the presence of PCBs, which goldfish don't produce.

So watch your water quality with that mix, and since skirt tetras are nippy, consider adding to the group if they harass the slow goldies.

I can't thank you enough for the replies. The temperature isn't great for the goldfish either way, but I have to keep it like this so it can be maintained all year round. (24 is my standard temperature.) If it's stressing for the goldies, I should probably try to keep it lower (it might be tricky) and, in addition, remove the tetras.
Naturally, I would prefer to keep them in the same tank because honestly, maintaining another is a bit difficult.
I am confident that the goldies won't eat the tetras, mainly because my goldies are still small.
So tetras like warmer water than this?
If (and it is a big if) I decide—based on your suggestion—to get them in another tank, how do I clean an unused, very dirty tank? How many litters would be okay for 3-4 tetras? (If I am going to change and invest time and money, I would probably buy 2 more for color variations.) Do they need an external filter like Eheim, or could a smaller filter do the trick?
thanks again for your help!

Those tetras can handle colder temperatures, down into the 60s F. They're Gymnocorymbus ternetzi, or skirt tetras, and they're found as far south as Paraguay and Uruguay where it's more subtropical in temperature.

So yes, temperature wise they would be fine with goldfish.


You do need to keep 6-8, not "up to 4" like the store clerk said. They get nippy in smaller groups, but given proper numbers these guys settle down and mellow right out. I won't shame on the glofish thing, I've had them before because my own kid and husband brought them home. They will get hate from people who prefer natural fish, but end of the day they can live just as long as the regular color skirt tetras (I had one live 6 years). If you and your kid like them, then enjoy them.


But watch their behavior with goldfish and make sure your parameters are really kept in check because goldfish are poop machines and produce a lot more nitrogen than many other fish. You'll find you'll want to really increase your filtration and make sure your tank size is upgraded as the goldfish grow. Goldfish eat plants, but anubias plants do well with them if you'd like to lower nitrates with live plants, and grow pothos out of the water is good as well.


Personally, skirt tetras wouldn't be ideal to keep with goldfish, but they're not the worst to keep with them either. You just mostly need to monitor for fin nipping and water parameters with keeping both, and you want a larger setup for the goldfish regardless of what you have. If they're fancy goldfish, a 4 foot tank would be alright for a small group, but if they're single tails, you need a 5 foot tank or more, or even a pond. They do grow fast and even fancies can get big.

Have you got fantail (double tail) goldfish or single tail fish?
Single tail goldfish can move faster and if they have short tails vs long, they will be less likely to be bitten by the tetras.

Goldfish can live in cold or warm water but need a cool period before it warms up if you want them to breed. Most goldfish come from and are bred in tropical Asia where the water regularly sits on 30C most of the year. I have had goldfish in tropical tanks for years and they are fine.

The glo-tetras (aka black widow/ skirt tetras) are renown fin nippers and need to be kept in groups of 10 or more. In small numbers (1-5 fish) they will stress out and probably start nipping fins. As CassCats mentioned, they can live in cool water down to 15-16C. If you want to keep them, get a bigger group and watch them closely. If they start nipping the goldfish you will need to separate them. Feeding the tetras more often so they are always full, will help to reduce nipping.

You could reduce the aquarium heater's temperature to 16-18C (depending on the heater) and let the water temperature naturally drop in cooler weather. Then it could go back up when the weather warms up. If the house has central heating and sits on 25C all year round, there's not much you can do about the heating except reduce the temperature or have the tank in a room without heating. Having said that, you want the fish in a room where lots of people move around it so the fish get use to people and don't stress when someone goes in the room.

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What sort of algae eaters do you have?
Chinese algae eaters are usually sold to people with goldfish but they get big and aggressive when they mature. Then they stop eating algae and eat the goldfish. A picture of the algae eaters would help us identify what species you have.

In the long run you might be better off getting another aquarium and just keeping the goldfish in that while the other fish can have their current tank. If space is limited you can buy or build double tier stands and have one aquarium above the other. This lets you have two tanks in the same space.

If you do decide to get another tank, get something that is at least 4 foot long. goldfish can get pretty big and most will reach 6-8 inches in body length (not including the tail) and many reach 10-12 inches in body length.

If you get a bigger tank and more goldfish, get the same tail type of goldfish to what you have now.
If you have fantails (double tail) then get more fantails.
If you have common goldfish (short single tail) get more common goldfish.
If you have comet goldfish (long single tail), get more comets.

hello again! I want to thank you again for the really valuable answers! (and your kindness)!

Now, I have to start by saying that my goldies are fancy. One of them is already around 8cm without the tail. almost doubled itself in 2 years. and the other is around 3-4.

My algae eaters are (most probably) indeed Chinese. -even if I recall a clerk calling them plecostomus-. One of them is bigger, the other is a tiny one added less than 8 months ago. Chinese species could explain that I find them to let more algae than used to like a year ago. I don't feed more than I did, but my anubia is not thriving, and my valisneria has gone. (Again, I can't be sure, but I have a small idea that they are different species, at least their color seems a bit different. One is lighter than the other).

I can verify that there is no aggressive behavior yet. I will add a camera again and monitor the behavior of ALL of them again.

For 6-7 months a year, it is not difficult to reduce the temperature. It could easily go to 20-22. I can start letting it drop to a pace, let's say 1oC per 24-48 hours, not to stress the fish. I have to confirm though that Tetras will accept that change. During summertime, I use a chiller, but I must probably upgrade this year because it's an old one.. Again, 22 won't be a disaster for me, but I want to verify about the fish.

For the time being, (and please verify), I have to buy some more tetras (I have to buy at least 4 more. Should I buy all 4 at the same time? or 2 and 2? should I wait for some days before that, so I can be sure that those first 2 didn't have a big impact in the ecosystem?) and check for the params regularly, like every 3 days or so. (I change 70% of the water each week). I also have to add pothos.

Now, as for a second tank, if I find a way to clean the old one I have, which is this one, I could try to fit it somewhere. But it would need a new filter, and new silicones (not leaking, but you can never be sure).

I am already thinking about what could I do to maintain the goldies. Upgrading seems the only way. A bigger tank won't be the ultimate solution (unless a 30-40cm bigger tank solves the problem).
A pond would be an amazing idea, but at this point way too difficult. It needs a lot of money, and MORE importantly (let's say I could find a way to create one myself with some help) it needs to address issues like security. My dog, my cat, or even other cats (a pond is for the yard) must be kept away. And it's not as easy as it sounds! This has to wait though, for at least a year, so I will have a fair amount of money to invest. (hopefully).

Your goldfish are comets (single tail, long tail).

The algae eaters are Chinese algae eaters. One is a gold and the other a pied. They like to hide during the day. You can put some pvc pipe in the tank for them, have one bit at each end of the tank. If you don't like pvc pipe you can smeer silicon on the pipe and roll it in sand or gravel to help camouflage it. You can also glue, tie or use rubber bands to hold plants like Java Fern on the pipe to help conceal it. the algae eaters will also hide under driftwood or ornaments.

The plants get eaten by goldfish and that is good for them. They need a lot of plant matter in their diet. You can buy a small floating plant called Duckweed and grow it outside in containers of water. Then bring some in each week and put it in the tank for the fish to eat.

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If you want to drop the temperature, reduce it 1 degree Celsius per month. If you want to drop is quicker than that, only drop it 1 degree Celsius every 2 weeks. You can reduce it to 18C and leave it there over winter then let it go up by itself in summer.
The fish won't eat as much in the cooler water so you won't need to feed them as often.

Why do you use a chiller in summer?
The fish will be fine in temperatures up to 30C for a few months each year if it gets that hot. If it only gets to 24-26C that can live in that for half a year without any issues at all.

If you want to add more tetras, do not drop the temperature until they have been in the tank for a month. They will settle in over a month and then you can start to reduce the temperature by 1 degree C every 2-4 weeks.

If you are going to buy more tetras, get them all at the same time so there is less chance of introducing a disease. They come in different colours so if you want purple, blue and yellow, get some of each. They are all the same species just different colours.

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I would put the empty aquarium outside somewhere in the shade and on a flat level surface. then fill it with tap water and let it soak for a few days. After that you can empty the water out and wipe the inside with a sponge or paper towel. Most of the gunk should come off pretty easily after a soak. Then if you want to disinfect it, you can wipe it out with bleach, wait 15 minutes then rinse well with tap water. If you don't like bleach, wipe it out with white vinegar and let it sit for a few hours or even over night. Vinegar won't harm the silicon but bleach will, so only have the bleach in contact with the silicon for a short time.

After it has been cleaned with bleached or vinegar, you rinse well with tap water, fill it up and let it sit for a few hours before draining and refilling a few more times. Then it should be fine to use.

Good silicon will be firm but slightly squishy. It should be the same colour all around. If the silicon is hard and brittle, it's stuffed. Bad silicon will usually turn cream/ white and might have bubbles in. If you post pictures of the silicon on the old tank, we can check it for discolouration and bubbles.

Those are comet goldfish, rather than fancies. They're going to get very large and the tank size you have will not be suitable longterm. They swim very fast, are very active, and grow large, so a 5 foot tank is mandatory for these guys.

You can also choose to rehome once they get too large for your tank, which would be relatively soon I'm afraid and that's also a doable option.

This is my single tail boy, he's still growing as well. They can get very good size and fast.



Both your algae eaters are indeed Chinese algae eaters, and these also grow large and turn more carnivore as they grow, they're known to attack the slime coat of tankmates once they do. Cool fish, but ones that also need specific set ups. They need large tanks with more aggressive tankmates who can hold their own with their behavior as adults.

Not everyone has space for monster size aquariums, and many folks are led wrong by petstore employees. Those aren't your fault, but it's something now to think about going forward. For two comet goldfish longterm, you'd be looking at a 568 liter (150 gallon) tank minimum to provide enough room to swim and water volume to keep up with their waste levels.

As for the photos of the old tank, it seems "repaired" but I can't recall doing it. I can't even recall asking someone to repair it. I couldn't eliminate it though. Adding photos so you can check. I already added water, so it can rest and it can be cleaned. (even if choose to keep them in the same with goldies, it is kinda cool to have an extra if needed). so far no leaks, but as I see the silicone, I will have to repair it anyhow. I don't want to buy a small one just for this.

As for the size of the goldies, @CassCats your goldie is QUITE big..
I 'm not sure when they ll be so big I couldn't keep them on the current. The problem with the big tank is that it will cost around 800-900 euros, which at this time I can't afford. I REALLY hope I have at least one more year until I will have to go that huge. A pond would also be a possible solution but it has to wait too.. HOPEFULLY next year I will have found a solution.

I will buy tomorrow both the plant and remaining fish, so I can continue. Should I buy both plants? Duckweed for growing outside and pothos for the nitrate?

About the temperature, it can EASILY get more than 30 for at least 2 months each year. I made a decision to let it around 24 all year round so I could prevent stress. If I leave it without a thermostat during winter or a chiller during summer, it can easily vary between 18 to 30 during the period of 5-6 months. April can be 20 and July 30.

I understand the expense part, and that's okay. You can also consider stock ponds, they're often cheaper than glass aquariums.



That's one I can find on UK Amazon

But these are what I'm mostly wondering about if you can find these where you are. They'd work for 2 goldfish for you and are much cheaper than the glass tanks.




Buy the pothos and duckweed, those are definitely worth getting now. Keep the pothos out of cats reach if your cats eat plants because they're mildly toxic to cats.



As for the other tank, let it sit for 7 days in your garage or such with it full of water, check for leaks.


Worst scenario, you wait until next year to set them up an outdoor pond

I can't thank you enough!
That pond is a great solution. It sure has delivery here. I m in Greece. A pond like this is way cheaper than I had in mind. (Obviously, and thankfully, it won't cost a fortune). The only problem (which I will have to solve) is that if I put it in the yard, it will be like a dream for cats, dogs, and other forms of life. On the other hand, it can't be placed (at least easily) on my balcony, because it will get really warm during summer and cold during winter. I will think about it.

Tomorrow I am buying the plants, and because I will grow them on my balcony, my cat won't reach them.

For now, there is peace in my tank, thankfully. I hope that it will remain when I add the rest tetras. Let's see how it goes!
I have to admit (nor that I ever tried to hide) that I love fish and aquariums. The bonus is that my daughter loves them too. (Hopefully, she will keep loving them).

I wouldn't worry too much about the temperature fluctuating between 18-30C. If it hits 30C for 2-3 months in summer they should be fine as long as it comes down to 18C in winter. The fish age quicker in warm water but giving them a cool period (18C) for several months in winter will help to compensate for that.

If you're really concerned, have the chiller set to 26-28C, but my tanks sat on 30C all summer (3 months) and dropped to 18C in winter. The fish were fine because the temperatures fluctuated slowly over months.

The problems that occur with temperatures are caused by sudden changes 5-10C over a few hours, days or a week.

Increase aeration/ surface turbulence when the water is warm so you keep the oxygen level high.

Do more frequent water changes in warm weather because the harmful disease organisms grow faster in warm water compared to cool water. Just make sure any new water is free of chlorine/ chloramine before it's added to the tank.

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Sorry, I should have been more specific about the pictures of the tank. After you have cleaned the old tank, get some pictures from the outside showing the edges where the silicon is. Looking along the outside edge (where the glass joins) will show air bubbles and white silicon easier than from inside. But give the tank a clean first and then check the silicon.