Fish Keep Dying Any Advice Greatly Appreciated.

Your fish are dying because you did not cycle the tank before buying them.
Fish excrete ammonia. This is toxic to them, but in a cycled filter there is a colony of bacteria which uses ammonia as food and convert it into nitrite. This is also toxic, but a second colony of bacteria in the filter uses nitrite as food and turn it into nitrate. This is only toxic at high levels.
This is what happens in a cycled filter, but a new tank and filter has none of these bacteria; they have to grow and this takes several weeks. Until then the toxins build up and poison the fish, causing what is called new tank syndrome. I know you added the Evolution Aqua Pure but it is unlikely to have worked. [The only ones that do work sometimes are Dr Tim's One and Only and Tetra Safe Start. The others contain the wrong species of nitrite-eating bacteria, and often dead bacteria]
The only way to keep these toxins from killing the fish is by doing water changes to remove them until the bacteria grow. Ideally, test for ammonia and nitrite twice a day and do a water change every time you see a reading for either of them above zero. The amount of water to change depends on how high the levels are. Some people find they have to do daily 50% water changes for a few weeks to keep the ammonia and nitrite under control.

Your test results indicate that you have grown some ammonia eaters or the level of that would be a lot higher. The nitrite eaters can't start to grow until the ammonia eaters have made some nitrite so the level of nitrite always peaks later than ammonia, and drops to zero later.
I would suggest you do a water change asap, at least 50% to get that nitrite reading below 0.25 [the highest safe-ish level, the only totally safe level is zero] then start testing every day. The results will tell you when to do the next water change.
Once you find the levels are remaining at zero without you having to do any water changes, the filter will be cycled. Then you can start doing weekly maintenance water changes of 25 - 30% to remove the nitrate before that gets too high.
But remember that you will have just enough bacteria to deal with the ammonia made by your current fish, and the nitrite made from that ammonia. If you buy more fish, the bacteria will have to multiply to keep up with the extra ammonia. For this reason, don't get a lot of new fish in one go. It is safe to add up to a third of the amount of fish already there in one go.


Guppies are weak fish nowadays; they are very inbred to get those pretty colours and breeders will use any fish whether it is a healthy specimen or not if it looks pretty. Guppies won't be able to cope well with ammonia and nitrite in the water. Shrimps are even more susceptible to them than fish.
Was the butterfly sucker one of these or perhaps one of the related species? These fish can be difficult to keep in a tank with 'ordinary' tropical fish as they need fast flowing, cooler water. It is possible that their need for cooler water, combined with ammonia and nitrite in the water, is what killed it.




Livebearers are quite easy to sex, though it is surprising just how many shop workers don't know. It is always worth checking the bag before buying and make them remove some fish if they've got it wrong.

Don't feel silly, tank instructions and shops rarely tell you what you need to know. I do wonder if it is because they don't understand cycling or because they think they'll frighten away potential customers.
You will probably find the filter instructions tell you to replace the sponges etc in the filter every so many weeks. Don't! You'll just throw away the bacteria you are trying hard to grow. I think the U series filters have sponges, ceramic noodles and poly-carbon pads? When they get mucky, wash the sponges and ceramics in old tank water that you take out during a water change, never under the tap. They will last for years. The poly carbon pads can be replaced, though again you can just wash those.


You may find it hard to find Dr Tim's as it is an American product. The Tetra one is sold in many shops, both real and on-line. The don't work every time as if the bottles have been handled badly during transport and storage at a warehouse, the bacteria can be damaged or killed.

A word of warning about shops - some of them will say anything in order to make a sale. It is safer to check out any fish on-line before buying. There is a database on here (fish profiles in the menu at the top) and I also use the site seriouslyfish which has a bigger database.