WHIRLWIND EXPLANATION: Pokémon have a fixed, permanent score from 0 to 31 for each stat that affects how good that stat can ever get.

This calculator will figure out that score (called a "gene" or, more obtusely, an "IV") for you, so you can discard the unworthy. It's more accurate for higher-level Pokémon, so it's helpful to go into a level 100 wifi battle with someone and check your Pokémon's stats from there.

Stat calculator

Feraligatr
Feraligatr 		Base
stats		 Stats Effort Stats Effort Possible genes (IVs)
Level Level
HP 85
277–307
30–31
Attack 105
212–243
31
Defense 100
203–233
31
Special Attack 79
161–192
31
Special Defense 83
169–200
31
Speed 78
159–190
31

Hmm, I need more information to figure out your Pokémon's genes exactly. Try raising it to level 100 and entering its new stats.
Remember: if your Pokémon battles at all, you'll need to track the effort it gains. Consider saving your game and using Rare Candy instead.

And for your copy/pasting pleasure:

30–31 HP; 31/31 Physical; 31/31 Special; 31 Speed

or start over