Need help emergency! Betta and cardinal terra

Bit of a long post but please read all PLEASE NOTE I am brand new to this and have only had my fish for around 1 week : I Have got a 30L tropical tank, which was left cycling for nearly 2 weeks before any fish went in. There is lots of live plants also some plastic ones, lots of hiding spots bridges etc. The water parameters were tested the day I bought my Betta fish and they were all perfect. I also got 3 neon tetras to go in with him. Did everything right when they first went in, they were happy and healthy, after a few hours of them being in the tank I noticed the Betta wasn’t acting normal was very lethargic and not happy, which I realised was maybe down to the water temperature (the lady in the shop told me to set it at 24C which I knew after reading online was wrong !) so I turned it up to 26C and the fish were happy again especially the Betta I seen a massive improvement in him. For about the first day or so he looked a tiny bit bloated which I figured was down to the stress from the cold temperatures also maybe over feeding, so I fasted him and the bloating seems to have gone. Then I noticed all fish were gasping at the surface, so I rushed out and bought an air stone to get more oxygen into the tank. This seemed to make the fish happy again and all seemed fine. After about 2 days or so one of the neon tetras died, then the following morning another one had died. I figured this was probably due to the stress from the cold temperatures as the tetras are more fragile than a Betta. I did a Partial water change (matched tank temperature, conditioned water with stress coat, stress zyme) and the Betta and the remaining neon tetra seemed happy and healthy. Another few days later I purchased 5 cardinal tetras (they are fine to school with the remaining neon tetra, in total there are 6 tetras). All seemed fine and healthy but then I started to notice my Betta looks like he has early signs of fin rot? So I have put Indian almond leaves in the tank today, some aquarium salt, cleaned some of the gravel and did another partial water change ( tank had a slight stinky smell so I wanted it to be okay). Since the almond leaves have went in the tank, my Betta started making bubble nests and I really don’t think the fin rot is bothering him (YET) as it’s very early stages and I feel like I’ve done everything I can do for him (don’t want to add any medication yet while it’s still mild). I was really happy thinking my fish are finally doing well and I can stop worrying and sitting by the tank nearly every minute of every day checking on them haha. I gave my Betta some bloodworms as a treat and he seems to be doing okay (apart from his fins). This is where I’m concerned, one of the cardinal tetras suddenly started isolating from the rest of them, then was up at the surface gasping rapidly and moving his gills rapidly, then I found him lying on the almond leaf near the surface literally dying it was horrible to watch. I didn’t know what to do for him (I have no clove oil to euthanise and I don’t think I could do that to him in case he had a chance of surviving somehow), then sadly he disappeared in the tank and I knew he had died somewhere in there. This was earlier on today and tonight I found him dead at the top of the tank with a huge chunk bitten out of his belly. I have removed him from the tank but now I am seriously concerned about the other fish in there? I honestly don’t know what I’m doing wrong I feel like I have tried everything, done extensive research, I keep my eye on them nearly all day every day to check how they’re behaving, water temp etc, only thing I have not got is a water testing kit which I know most of you are going to say to me first, which I thought because the parameters where fine then the water would still be, and the Betta would be acting strangely but he seems really happy and healthy? I hope someone can help me, I love my fish and don’t want to see another one day (especially not my gorgeous Betta) !
NOTE : this may not be relevant, but I have been comparing my Bettas fins to when I first got him, and when he came to me he seems to have this weird part of his tale that is significantly shorter than the rest of his tail, almost as if he has either bit it off in the shop then it has started to grow back, or he has had fin rot in the past and this is it growing back, or it could be just his natural tail, I can attach photos if anyone wants thank you so much for reading xxxx

Also if someone can help with the water changes, should I be doing them daily? Or not so often as the tank is still fairly new and I don’t want to remove any beneficial bacteria and stress my fish with the constant changes?

Could you post the pics?

Also walk me through the process you used to cycle the tank. Did you add ammonia?

Beneficial bacteria lives in your filter and other surfaces in your aquarium, not in the water. So you won't hurt it by doing water changes.

It sounds to me like your tank is not cycled and you're having water quality issues. Do you have a test kit, or can you get one?

JuiceBox52 said:

Could you post the pics?

Also walk me through the process you used to cycle the tank. Did you add ammonia?

Click to expand...

Hi I am new to the site so still figuring out how to post pics, and the lady in the store (numerous of them actually), said the ammonia will come from the fish waste (which is why I only had 4 fish at first then added more later on)

WhistlingBadger said:

Beneficial bacteria lives in your filter and other surfaces in your aquarium, not in the water. So you won't hurt it by doing water changes.

It sounds to me like your tank is not cycled and you're having water quality issues. Do you have a test kit, or can you get one?

Click to expand...

Hi I am going to take a water sample to the store today to have it tested, I immediately thought about the water quality but the fish seem really normal in their behaviour this is why I thought it was down to the cold temperatures when they first went in, but obviously if the tetras are dying there is something wrong. Today all fish seem to be doing fine tetras are bright and swimming normally, Betta is having fun building his bubble best and seems his usual self. One thing I should mention though, I keep the heater at 26/26.5 Celsius although last night around 3am I came down to check on them (I know I’m crazy haha), and the stick on thermometer was reading 24 degrees what the hell!?? I adjusted the heater slightly up and now it’s back to its usual 26, the fish were asleep when I came down to check them (I turn the lights off at night and they all sleep in their usual spots) so I hope it never affected them much as the temp couldn’t of been dropped for too long as I had checked them an hour prior and they was fine also checked them again early morning and temp had gone back to normal. I really feel so unlucky with this whole fishkeeping thing I really hope I can fix my mistakes and give my fish a long healthy happy life

It’s so hard to get a photo of him and his tail, first photos are last week, last photo is today

I put the floating mirror in to get him to flare his tail for a photo

Hey Ap
Ok so, the lady at the petstore didn't really give you the best of advice. She advised for a fish-in cycle which is really stressfull for the fish and oftentimes they don't make it. The cloudiness in the water is a bacterial bloom , the nitrifying bacteria are now starting to show themselves.If I were you I would change 50% of the water daily and test my water every 3 days and updating us ( I higly suggest you get a test kit)
By doing daily water changes you will protect your fish from the toxic ammonia and nitrites until the nitrifying bacteria have been well established. You will understand that they have been established by the measurements when the water has 0 ammonia 0 nitrites and soem nitrates some nitrates (before the WC).Have you read about the nitrogen cycle in depth?
I would also remove the plastic plants to stop the bettas fins from tearing even more
side note: The daily water changes should also help with the fin rot
Are you using a dechlorinator?
How are you maintaining the filter?
The 24 celsius shouldn't really affect your fish that much so don't worry about that .

Yeah, the slightly fluctuating temps aren't your problem. Bettas seem to prefer it a bit warmer than 24c, but that won't cause the problems you're seeing. Here's what you need to do:
1. Get a test kit. If your store doesn't have one, look up API Master Test Kit on amazon (or whatever the English equivalent of Amazon is...) You really should test every day at this stage (you can slack off on that once things stabilize) and you aren't going to want to take samples to your pet store every day.
2. Read up on cycling. It's too late for you to do a fishless cycle, since you already have fish, but it's good to know for the future.
3. Until your test kit is showing 0 ammonia and 0 nitrites, keep doing the water changes every day. This might take up to several weeks. Make sure your new water is from the same source and the same temperature as the existing tank water, so you don't shock your fish.
Alternately, you can get some Seachem Prime, a liquid water conditioner which detoxifies ammonia. Follow the instructions on the bottle carefully. Again, you might need to do this for several weeks.
4. Don't despair. You aren't "unlucky with this whole fishkeeping thing." You got some bad advice from the pet store. That's normal, and it isn't your fault. Pet sore employees are notorious for giving very, very bad advice. Most of us have had the same problems you are having--we were all beginners once too. This is why most people get a fish, it lives for a few weeks at most, then dies. If you want to go beyond that, there are some things you have to learn. But fish keeping doesn't require magical powers or luck. (OK, sometimes luck is part of it) Just a few key bits of knowledge and a willingness to do what you need to do.

WhistlingBadger said:

amazon (or whatever the English equivalent of Amazon is...)

Click to expand...

Amazon.co.uk

WhistlingBadger said:

Alternately, you can get some Seachem Prime, a liquid water conditioner which detoxifies ammonia. Follow the instructions on the bottle carefully. Again, you might need to do this for several weeks.

Click to expand...

Prime also claims to detoxify nitrite.

The detoxification effect wears off after about 24 hours so ammonia and nitrite become toxic again. Water changes still need to be done whenever there is a reading above zero but Prime will keep the fish safe for 24 hours.

Prime should only be added to new water at a water change; it should not be used as a medication and added to the tank without a water change.

I would also suggest you pick up some fast growing floating plants that will help absorb the ammonia. Plants like moneywort, hornwort, pennywort, anacharis, frog bite and water sprite will help. If you pick up enough you may be able to do a planted cycle with the plants taking care of the ammonia but you are starting off with cardinal and neon tetras which are not a good fish for starting any cycle, they are sensitive to water chemistry changes .

Hi everyone thank you sooo much for your advice! To be honest the internet gives me better advice than anyone in the pet shops, I had my water tested and the ammonia was near enough dark green in the bottle (don’t think it’s sky high but near enough), and the nitrite was higher than it should be, I have changed about 40-50% of the water, the girl told me there’s no point in testing again until around next week after daily water changes. I have added stress coat stress zyme and matched temperature, so I will do this daily. You are abseloutely right about the tetras I won’t be adding any more for around another few weeks when water is better and my Betta has healed. Also I am going to add more plants to absorb the ammonia definitely, also my fish are going to have to starve for a few days haha because I’m not adding any more food. Also, should I remove the almond leaf? Will this do any damage regarding the ammonia and nitrite? It has only just sank to the bottom I haven’t ripped it apart so it should take longer to start decaying. Thanks again everyone !

As fas as getting tetras in a few weeks I would suggest holding off on neon and cardinal tetras until your tank stablizes which can take up to 6 months. I lost several neon when I put them in too early. A good tetra to think about is a glow light tetra, nice looking and hardier than the neon/cardinal tetras. I currently have 14 of them in my 55 gallon tetra tank and have not lost any.