Toddler Has Over Fed Tropical Fish.. Please Help. SOLVED

I have a 55 litre aquanano tank with 7 male guppies, 6 neon tetras, 1 baby Molly, 2 shrimp & 2 snails.
It has taken me about 9 months to get to grips with caring for these fish & I have really enjoyed it. For months now all levels have been tested & are normal & I haven't had any diseases (that I know of) or losses.
My toddler found the fish food out of the cupboard (very large tub) & poured it into the tank yesterday. I managed to salvage about half of the water but the rest was too murky. The fish are not happy. The guppies are constantly at the top of the tank & the shrimps are next to the opening of the filter all of the time which isn't like them, they are always tucked away in the day.
Levels aren't great.
PH is 7.6
Ammonia is 0.25
Nitrite is 5.0
Nitrate is 160

Is this tank doomed or is there anything I can do to salvage it?

Thank you in advance

Caren

Thank you so much for your advice. I will try this.

You'd be surprised how often this happens, most people report saving their tanks by all those water changes. Not to mention people measuring out the food over the tank and dropping the tub in.


And put the food, and everything else, somewhere the toddler can't reach it 

It is safe to change all the water provided that you use dechlorinator and if you change a lot in one go that the water is heated to near the same as the water left in the tank.

You won't harm the bacteria as they live in the biofilm which is bound onto surfaces. You'll only harm the bacteria if you forget the dechlorinator or scrub the surfaces so hard you dislodge the biofilm. And by surfaces I mean the filter media, the filter casing, the decor, the glass etc.

Your readings of ammonia and nitrite should come down as you remove them with water changes, and remove the cause ie the fish food. Fish food decays to make ammonia which the first set of filter bacteria turn into nitrite. They multiply faster than the second bacteria which turn nitrite into nitrate. And 1 ppm ammonia is turned into 2.7 ppm nitrite. Both of these are why the nitrite reading was a lot higher than the ammonia reading.

Thank you for the advice & I will keep you updated.

After a few water changes the levels have all gone back to normal & the fish & shrimps seem back to their happy selves.

Thank you all for your help & advice. I appreciate it.

Awesome 

Excellent news...... now, how about some piccies of your happy tank?! It's the rule, you know.

This is when disaster struck!