Tizer
Team TetraTEC
Your fish are small but they wont die over night, nor will they die within the next few weeks. From the sound of things they are very young and probably do have enough space for now. However, the problem is, it sounds like your tank is not correctly cycled and they are swimming around in ammonia/nitrite, basically urine.
I suggest you change 50% of the water in the tank with tap water every day until you can return them. Try and match the temperature with the tank using a little bit of hot water, it will do no harm.
When you are in a position to start fresh make a post with a more details description of the items you have including the filter and several people here will set you on the right track.
While you are in the shop pickup a liquid test kit, or even better grab one off eBay, API Freshwater master Kit comes highly recommended by many people here. Also pickup a bottle of water dechlorinator to remove chlorine from the tap water. Reasons for its use, again can be found in the beginners section.
Take things slowly and just absorb the info a little each day and things wil become clear.
What you need to understand is that 25 Litres is very very small for a tank and the smaller the tank the harder they are to manage and because of the small volume of water you have to play with, the quicker it becomes toxic to the fish.
My recommended size for a first tank would be 90 litres, its not too big and its not too small, but if you can get hold of the 50 litre then thats also a good start.
I suggest you change 50% of the water in the tank with tap water every day until you can return them. Try and match the temperature with the tank using a little bit of hot water, it will do no harm.
When you are in a position to start fresh make a post with a more details description of the items you have including the filter and several people here will set you on the right track.
While you are in the shop pickup a liquid test kit, or even better grab one off eBay, API Freshwater master Kit comes highly recommended by many people here. Also pickup a bottle of water dechlorinator to remove chlorine from the tap water. Reasons for its use, again can be found in the beginners section.
Take things slowly and just absorb the info a little each day and things wil become clear.
What you need to understand is that 25 Litres is very very small for a tank and the smaller the tank the harder they are to manage and because of the small volume of water you have to play with, the quicker it becomes toxic to the fish.
My recommended size for a first tank would be 90 litres, its not too big and its not too small, but if you can get hold of the 50 litre then thats also a good start.