Rainbow fish attacking everyone in my tank!!

[FishNewbie82912]

Tank consists of:
3 guppies
3 glo fish tetras
2 glo fish danios
1 ballon molly
1 rainbow
1 dwarf gourami
3 Cory

Tank size: 25 gal
pH: 7.4
ammonia: 0.25ppm
nitrite:0
nitrate:10ppm
kH:
gH:
tank temp:80

Volume and Frequency of water changes: 7 gal weekly. I did a change today.

Chemical Additives or Media in your tank: API stresscoat and quick start with changes. I also add salt (tiny bit) as i had ich a couple weeks ago or what I thought was ich. Not sure. Cleared up fast with salt and higher temp. I keep a little salt now to ward off disease

Recent additions to your tank (living or decoration): I fixed a plant with hot glue gun 3 days ago and Added the new guppy 4 days ago. I had a ballon Molly I added 8 days ago but he died this morning. So had to replace before my son noticed and when I put him in the rainbow fish has been attacking him and everyone else. Although he’s really going for the new molly. His colors changed like crazy too. He looked like I colored him with a yellow highlighter from his nose to his fin which I have never seen before. He’s farting at everyone. Side note my new guppy’s fin was split in half yesterday. I added melafix but decided it was from an injury doesn’t look diseased. My snail died the other day too. Not sure what the hell is going on. I’m not good at this fish tank thing and its stressing me out. I also bought the tetra safe start plus to help with my ammonia. I added 8ml. I get my new filter (fluval 40-70gal) to replace the one that came with my tank (top fin 30gal) to hopefully help with my overcrowded fish tank. My son and I love to get a new fish every time we go to the pet store.

Exposure to chemicals: don’t think so

Posted this to tropical emergencies as well

 

[Byron]

What species of rainbowfish? These are shoaling fish, which means they must have a group of the species. When this is not provided, it causes stress, and the fish reacts usually with aggression. This is basic to all shoaling species (tetras, danios, barbs, rasbora, cory catfish, and some others). However, simply acquiring more is not usually the solution when it is as pronounced as it may be here. And the tank may not be sufficient space; can you post the dimensions please?

It would also help to know your water parameters, which refers to hardness (GH, KH) and pH. You have fish generally requiring moderately hard or harder water, though a few are on the moderately hard to soft side.

Ple3ase resist the urge to acquire fish. As noted above, you have several species that need a group; six is generally considered minimum though more will always be better for the fish. Tank space will undoubtedly limit this, which means removing/re-homing some. When we know the tank specs and the water data we may be able to better suggest which need to go.

Discontinue the salt, there is absolutely no "preventative" benefit from using salt in a freshwater aquarium. At low levels it can do nothing, but at any level it seriously impacts many fish, here the cories, gourami, tetras, danios, possibly rainbow... .

You need to be changing much more water at one go. Once a week is fine, but change at least half the tank and preferably more; given the circumstances here I would change 65-70% weekly (at one go, this is far more beneficial than smaller more frequent changes).

Adding substances is never advisable unless it is a specific medication/treatment for a certain disease. Clean water is the best remedy for much, and certainly the best prevention. Use a good conditioner, nothing else. Stress Coat contains aloe vera, now known to interfere with fish gills long term.

The ammonia at 0.25 is likely not an issue. I won't go into that now as there are the other more important issues to deal with.

 

[seangee]

I'm afraid there is a lot of stress going on in your tank.
Rainbowfish should be kept in groups of 6. So should tetras, danios and corys. However as you point out your tank is already overstocked, so please do not buy any more fish.
Aggression is one way that fish react to stress.

I should also point out that you have a mix of hard and soft water fish in the same tank. Some of these fish will likely suffer health issues. You have not posted your hardness readings but the reason I have commented is that you mentioned the death of a molly. Mollies require very hard water and if your water happens to be soft they will keep dying. If your water is suitable for mollies a lot of your other fish will have very short lifespans. It is not adviseable to add salt as a preventative measure. It can be useful in specific circumstances but not permanently, especially not with cories in the tank (they are sensitive to salt).

Are you aware of the filter cycle? If not it is worth reading this link. When your new filter arrives you should run it alongside the old one for at least a month while it builds up the neccessary bacteria. Removing the old one before the new one is established will cause serious health issues, and probably dead fish. Apologies if you already know this but posts where people have simply swapped out filters and then start losing fish are quite common in the Tropical Emergencies section.

 

[FishNewbie82912]

Ugh I feel so defeated. at pet smart they make it sound like all these fish get along and no one ever informed me of these things. I’m so annoyed. Well I’m definitely done adding fish. I will read the link about the filter.
I had a black molly that lasted months before passing. I’ve also long a zebra barb, a snail, and a blue guppy. I’ve had the tank since February. So I thought I was doing kind of good until recently. Everyone seemed happy and healthy.

 

[Byron]

Ugh I feel so defeated. at pet smart they make it sound like all these fish get along and no one ever informed me of these things. I’m so annoyed. Well I’m definitely done adding fish. I will read the link about the filter.
I had a black molly that lasted months before passing. I’ve also long a zebra barb, a snail, and a blue guppy. I’ve had the tank since February. So I thought I was doing kind of good until recently. Everyone seemed happy and healthy.

Many of us began under similar circumstances, or should I say, disasters. I know I did. One thing you hopefully have learned, is never assume the staff in a fish store are providing good advice. Now you are on this forum, ask here beforehand. It can safe a lot of grief, fish losses, and disheartened children.

We need to pin down the GH and pH. Assuming you do not have these tests, you should be able to check with your local municipal water authority, they may have a website with water data, or you can contact them directly. We need especially the GH (general or total hardness) and the pH. Get the number, and for the GH also their unit of measurement as there are several. Once we know this data we will have a better idea of suitable fish to move forward.

 

[FishNewbie82912]

Many of us began under similar circumstances, or should I say, disasters. I know I did. One thing you hopefully have learned, is never assume the staff in a fish store are providing good advice. Now you are on this forum, ask here beforehand. It can safe a lot of grief, fish losses, and disheartened children.

We need to pin down the GH and pH. Assuming you do not have these tests, you should be able to check with your local municipal water authority, they may have a website with water data, or you can contact them directly. We need especially the GH (general or total hardness) and the pH. Get the number, and for the GH also their unit of measurement as there are several. Once we know this data we will have a better idea of suitable fish to move forward.

Okay well I’ll get those tested ASAP and post again. I have a feeling that rainbow is going to eat my molly!!! I’ve never seen him act like that. And change colors so quickly. It’s crazy.

 

[Byron]

Okay well I’ll get those tested ASAP and post again. I have a feeling that rainbow is going to eat my molly!!! I’ve never seen him act like that. And change colors so quickly. It’s crazy.

The fish need to be separated. The stress this is causing the molly is significant enough to weaken it to the point of death. The Rainbow is not going to give up. I cannot tell you what to do, obviously, only what has to occur. The best solution short term is to remove the Rainbow in order to calm things down, then move ahead and decide which fish stay and which may not.

 

[FishNewbie82912]

The fish need to be separated. The stress this is causing the molly is significant enough to weaken it to the point of death. The Rainbow is not going to give up. I cannot tell you what to do, obviously, only what has to occur. The best solution short term is to remove the Rainbow in order to calm things down, then move ahead and decide which fish stay and which may not.

Thank you. What do I do with him overnight? I don’t have a back up tank set up? And why would he just decide to all of sudden act so aggressive to this new guy? I’ve had the rainbow longer than most and he’s always been fine. At least what I observe. Now I’m wondering if he frightened that other balloon molly to death and ripped the guppy tail!

 

[Colin_T]

His colors changed like crazy too. He looked like I colored him with a yellow highlighter from his nose to his fin which I have never seen before.

It sounds like the rainbowfish is a male and he is showing off to the molly. Male rainbowfish get a coloured stripe that runs from the front of the dorsal fin to the top of the mouth. It is usually white or yellow in colour and they can flash it on and off. They flare their fins out and get a lot more colour when showing off too.

If you have a male molly that is similar size to the rainbowfish, then the rainbowfish will spar/ show off and display to the male molly or any other male fish that are similar sized to him. Adding a couple of female rainbowfish will let him display to them and he will spend less time harassing the molly. However, he will still display to the molly if there are no other male rainbows to display to.

Rainbowfishes should be kept in groups of 6 or more and the groups should have even numbers of males in (eg: 2 males, 4 males, 6 males), and it should contain females. Try to have males that are the same size as each other so big males can't pick on smaller males.

If you can post a picture and short 30-60 second video of the fish doing his thing, I can confirm the above.
If the pictures are too big for the website, set the camera's resolution to its lowest setting and take some more. The lower resolution will make the images smaller and they should fit on this website. Check the pictures on your pc and find a couple that are clear and show the problem, and post them here. Make sure you turn the camera's resolution back up after you have taken the pics otherwise all your pictures will be small.

If the video is too big for this website, post it on YouTube and copy & paste the link here. We can view it at YouTube. If you are using a mobile phone to take the video, have the phone horizontal so the video takes up the entire screen. If you have the phone vertical, you get video in the middle and black on either side.

-------------------------
However, as others have mentioned, you have species of fish that come from soft water and some species that come from hard water. And I don't recommend adding new fish to a tank if a fish has died recently. If a fish dies, you should do a 75% water change and gravel clean the substrate every day for a week. This will dilute any disease organisms and help prevent other fish getting sick and dying. Make sure any new water is free of chlorine/ chloramine before it's added to the tank. If the fish are fine for at least 2 (preferably 4) weeks, then add more fish.

Your tetras, danios Corydoras and rainbowfish all need to be kept in groups of at least 6 and preferably 10 or more (especially the tetras and danios, which stress when kept in small groups).

Try to avoid keeping balloon mollies or any type of balloon fish because they don't do well due to being genetically deformed and having their internal organs squished up.

-------------------------
For the long term health of the fish, I would suggest either getting a second tank for the rainbowfish, molly and guppies, or just keep one tank with fish that come from hard water or soft water but not both.

Rainbows, guppies and mollies do best in water with a GH (general hardness) above 200ppm (250ppm for mollies) and a pH above 7.0.
Tetras, Corydoras and gouramis naturally occur in soft water with a GH below 150ppm and a pH below 7.0.
Danios come from soft water with a GH below 150ppm and a pH around 7.0.

Your water has a pH of 7.4 and that is fine for all the fish. But you should try to find out what the GH is. This information can usually be obtained from your water supply company's website or by telephoning them. If they can't help you, take a glass full of tap water to the local pet shop and get them to test it for you. Write the results down (in numbers) when they do the tests. And ask them what the results are in (eg: ppm, dGH, or something else).

 

[Byron]

Thank you. What do I do with him overnight? I don’t have a back up tank set up? And why would he just decide to all of sudden act so aggressive to this new guy? I’ve had the rainbow longer than most and he’s always been fine. At least what I observe. Now I’m wondering if he frightened that other balloon molly to death and ripped the guppy tail!

Colin answered in detail about the behaviour, but given thee circumstances here I would tend to think it is more likely aggression from sheer frustration at being alone. The two explanations are actually part of the same thing anyway.

Shoaling fish have an inherent need to be in the company of their own species. This is programmed into the species' DNA. When the fish is being maintained contrary to what it expects, it experiences stress. In fish just as in all animals including humans, stress can build until something breaks and the fish suddenly changes behaviours.

This is a different aggressive behaviour from that some fish have regardless. In other words, an aggressive species will always be aggressive. But when stress is strong enough to affect the fish's normal behaviour, what we term chronic stress, that is what you are seeing here.

Aggression is the usual response to chronic stress because it is just about the only means a fish has of lashing out over its frustrations. To use human terms, the fish has "snapped."

You have to get rid of this rainbowfish, meaning, remove him from the others. And to be honest adding more of that species, even if you had room, would not solve this problem because the stress has permanently affected the fish.

 

[FishNewbie82912]

Colin answered in detail about the behaviour, but given thee circumstances here I would tend to think it is more likely aggression from sheer frustration at being alone. The two explanations are actually part of the same thing anyway.

Shoaling fish have an inherent need to be in the company of their own species. This is programmed into the species' DNA. When the fish is being maintained contrary to what it expects, it experiences stress. In fish just as in all animals including humans, stress can build until something breaks and the fish suddenly changes behaviours.

This is a different aggressive behaviour from that some fish have regardless. In other words, an aggressive species will always be aggressive. But when stress is strong enough to affect the fish's normal behaviour, what we term chronic stress, that is what you are seeing here.

Aggression is the usual response to chronic stress because it is just about the only means a fish has of lashing out over its frustrations. To use human terms, the fish has "snapped."

You have to get rid of this rainbowfish, meaning, remove him from the others. And to be honest adding more of that species, even if you had room, would not solve this problem because the stress has permanently affected the fish.

What do I do with him? It’s not any better today. It’s really just towards that new molly. He stakes him out and then darts at him. Then he starts flaring his fins and twitching in front of him. And now he keeps rubbing against the molly and twitching. Ugh I’m so sad. The rainbow is my favorite.

Update: I removed the molly into a glass vase and the rainbow has calmed down a bit. I can tell he’s searching for him. I don’t know what to do with my molly now. How long can he last in a vase?

 

[Colin_T]

And now he keeps rubbing against the molly and twitching.

LOL, he's got the hots for the molly and is having sex with it

Either
Get rid of everything except the Cories and rainbow and get some more rainbows.
Get another tank and move the rainbowfish into it and add a few more so there is a group of them.
Get rid of the rainbowfish, guppies and molly and get more tetras, danios and Cories.

 

[FishNewbie82912]

LOL, he's got the hots for the molly and is having sex with it

Either
Get rid of everything except the Cories and rainbow and get some more rainbows.
Get another tank and move the rainbowfish into it and add a few more so there is a group of them.
Get rid of the rainbowfish, guppies and molly and get more tetras, danios and Cories.

Hahahah I wish it was affection. This does not seem like good feelings. I’ll see if I can convince my husband about a new tank. This was supposed to be the easy answer to avoiding getting our kids a dog. Jokes on me I guess.

 

[Colin_T]

If you go to YouTube and search for rainbowfish displaying, there are lots of videos that show male rainbowfish displaying to other fish. The following link is an example of a male Melanotaenia lacustris displaying and showing off his gold dorsal blaze (the strip from the dorsal fin to his mouth).

 

[FishNewbie82912]

If you go to YouTube and search for rainbowfish displaying, there are lots of videos that show male rainbowfish displaying to other fish. The following link is an example of a male Melanotaenia lacustris displaying and showing off his gold dorsal blaze (the strip from the dorsal fin to his mouth).

Yes! That’s exactly it!! It startled me because I’ve had him for 6 months and never saw that! Truly beautiful fish. If I decide to move some fish could I get more rainbows in my 25gal? I really don’t want another big tank. I have wanted a small tank for my bedroom so I wouldn’t mind that.