When I had a fish tank in west Oxfordshire, England, we had neon tetras which were fine. I don't know what the water hardness is like in Oxfordshire though.
Now I live in North Wiltshire and setting up my own tank. I think the water is quite hard where I live as lime scale build up is quite a problem, as it often has to be removed from around the sink etc. I'm told water hardness is connected to the PH level.

As I haven't kept fish for quite a while, thought it's a good idea to watch youtube fish keeping videos to refresh my knowledge, and a video said you shouldn't keep neon or cardinal tetras in hard water. I assumed I should look for another type of fish more suited to hard water and forget about Neon or Cardinal tetras. Although while I was in Pets at Home in Swindon buying supplies to set up the tank, thought I would ask person who specialises in the fish, and she said, yes if the fish were taken from the Amazon soft acidic water, then they wouldn't last in a different type of water, but they have been bred and kept in Swindon water so used to it, they will do fine.

The video saying tetras should be kept in soft water was by a man in the USA, so maybe they're more likely to have fish from the Amazon?

What do people think on here? Should I still get Neon or Cardinal Tetras, or go for another type such as Platies more suited to hard water?

I'm afraid the person in the shop wasn't telling the truth as tetras cannot breed in hard water. Any bred in the UK are bred in soft water - either RO or rainwater. Plus, that shop buys its fish in from wholesalers who source fish from foreign breeders and wild-caught, not local bred.

The first thing to do is to find out how hard your water actually is. You can find out from your supplier's web site. Look for a page on water quality in your area, input your postal code and you'll get a full report including hardness. You can then compare your hardness to the requirements of the fish on a site like this one, or https://seriouslyfish.com/knowledge-base/

Even if you can't keep neons or cardinals there are some tetras that can cope with harder water (depending on how hard). Pop back with your hardness level and we'll see if there are any that are suitable.

Oh thank you. My water supplier gave me the hardness information when I put in my post code.
It says very hard, but also measurements which I don't understand the meaning of.
I have taken a screen shot of the information it gave me.
I have tried to attach the image to this message. Hope it works.

Hi

The figures we use in fishkeeping are ppm of calcium carbonate or German degrees. Your water is very hard and the only tetra I can come up with that can cope with it is the X-Ray Tetra, Pristella maxillaris. Have a look here for more about them and some pictures: https://www.seriouslyfish.com/species/pristella-maxillaris/

Just thought - also False Penguin Tetra, Thayeria boehlkei and Red Eye Tetra, Moenkhausia sanctaefilomenae

Thank you. Reason I was interested in the Cardinal or Neon tetra is because of the colours, and ones you suggest aren't that colourful.

Maybe I should go with another type then, such as Platies.

Male Endler's Livebearers (Poecilia wingei ) are very colourful. You could have an all-male group to avoid breeding. https://www.seriouslyfish.com/species/poecilia-wingei/

Went to have another look in the fish store, and woman in shop only seems to think minnows are suited for a new rank. Even though it has been running about a month. I would prefer Platy though.

If the tank has been fully cycled with ammonia you can stock any species. If it hasn't then that needs to be done as no fish should be put in an uncycled tank. This article explains why a fishless cycle is necessary and how to do it: https://www.fishkeeping.co.uk/articles ... hless-cycling-article.htm

Yes I've been running my set up tank with filter and plants for a while, and added the fast start bacteria from the bottle.
I'm going to get the water tested before adding any fish.