First 10Gal tank and had a couple fish die after only 2 days. Help!

[JMarg7]

Hello,
My roommate and me are new to all this. My roommate had got a male beta about 7 months ago and set up a 2 Gal tank for it. The ammonia spiked in that set up and ended up killing the beta.

We then went and got a 10Gal tank. We let the tank cycle for a bit and after testing the water and getting all levels good we introduced a female beta. 2 days after that we introduced 1 female platy and 2 male fancy guppies.

Waking up after the first night we discovered the beta appeared to attack one of the guppies and injured it’s tail. As well as finding the platy dead.

We put the injured guppie in a breeding box net to separate and let heal, but by end of day he died.

The remaining guppie seems to but struggling as well. We aren’t experienced or knowledgeable enough to really know what we are seeing, but seems like the guppie is gasping for air. He’s at the top of the tank a lot and opening and closing it’s mouth rapidly.

We just changed about half the water in hopes this will help get the guppie through the night and level things out.

Does anything I said stand out to anyone as to what went wrong or what can we do better at so this won’t happen. My roommate is so disheartened and wants to give up, but I know how much joy the fish bring her so I really want to learn more and figure out what happened and what to do. Any and all advice is great appreciated. Happy to answer any additional questions there might be.

Thank you all in advance for the help.

 

[Lynnzer]

Bettas may look so serene and sort of casual but they are an aggressive fish. Sometimes they can integrate into a community but it's a risk.
If you want a community tank with different species of fish then I'd take the betta back to the shop and consider other options.
It's important to comply with the needs of the fish too, which includes the sort of water they thrive in. Steer away from fish that do best in hard water if you are in a soft water area, and vice versa.
If you can post here the water parameters of your local supply, we can suggest suitable species for you. The shop you bought the tank and fish from should be able to test the water for you if you take a sample in for them.
From a quick search it seems you are in a hard water area that, at least means platys should be OK and guppies possibly not. Mollies are hard water fish too if you like that sort of fish. I'm no expert on that though and others will drop in and suggest other things.
However, also consider the mix of fish too. A single guppy and a single platy is a bit like putting one of each republican and democrat supporters in a small room together. They need to be part of a group, not lonely distanced tankmates.
I do like to blow my own trumpet when it comes to letting people know about the pleasure I get from actually building an aquascaped tank and a lively, lovely community of fish and to that end I have a live webcam stream of one of my tanks. The one shown right now, though not all the time, is my last effort. It has a pair if Badis Badis, 12 (I think) green neon tetra, and 4 male endlers along with a few King Kong Shrimp and 4 Oto's to keep the tank algae in check. Take a look, though due to the time difference the room my be unlit at times.

 

[FishPal]

Are those bubbles in the back being produced or is that part of the background?
Could be too much oxygen, but that comes with other symptoms as well, if the betta is still alive and seems fine, maybe just too aggressive for more fish. With this, sometimes you can, sometimes you can't, depends on individual temperament really.. think, when you get stressed or have anxiety, breathing can sometimes feel difficult, might not be the water levels, but stress showing symptoms.
Have you checked ammonia levels and everything else though in case?
What all is involved in your setup?
If everything seems to match what's necessary, could just be stress.
Do you acclimate them properly with enough time?
I had multiple fish die at first, but I had added fish before fully cycling my tank.
I'd check parameters again, and research species to make sure everyone is ok with their homes.

 

[FishPal]

Agreed to respect the fishes needs too. That alone will help tremendously with your success. We often downplay their needs. We also often want what we want in a tank, but the political example was a good one!! Even if same water requirements, some just don't and can't mix!

 

[Lynnzer]

Your 10 gallon tank is probably best with nano fish too. You can keep a decent number of them and they won't create as much waste as larger fish so keeping the water right will be easier.
Your tank is much the same sort of size as the one I showed you and I think you can see the effect of a decent setup. My wife hates me keeping fish as it really prevents weekends away and holidaying for a week or so, but she still loves sitting watching the interaction of the fish. Watching a guppy, or a platy or a betta even, though are pretty, isn't like watching a community of small same species or a mixed community of similar sized fish.
Think of it like this: would you pay to watch a football match where only a couple of players come onto the pitch, or would you like to see the full team?

 

[Naughts]

keeping fish as it really prevents weekends away and holidaying for a week or so

Why? They can be left without food for a few days.