Where is the Purple Tootfish

This problem has different solutions depending on how you want to play.

If you're just looking for the achievement, one solution to your problem is to do whatever missions you want, choosing the side of good, until you get relatively close to your level point. Then go into a town and steal (for minor karmic reduction) or lay waste to entire towns (for major karmic reduction). You can quickly lower your karma this way. Then, once you're neutral, go kill some random creatures until you level.

(If you're looking to steal, a good place to do it is at Dukov's place… he's got stuff everywhere.)

The "nice" thing about this system is that if you stay on the path of "good" the whole time, you can do this at each achievement point: be bad until you get to the right karmic level, level up, get your achievement, and then restore a save to get back to your good self. You can quickly get "good", "neutral", and "evil" achievements for all levels on one playthrough this way.

(I did this, because I don't really enjoy long-term playing as an evil character… but I do like my achievements!)

You could also do this as an evil or neutral character, but it's much easier to quickly drop from "good" down to your new goal, than to work your way up.

If you find that you're close to leveling, and you're at the right karmic level, and don't want to take a chance on changing your Karma by doing a story-type adventure, you can always go wandering looking for random bad people to take out. Going near the Washington Mall can get you some XP fairly quickly, and you can go inside the capitol building and clear out large areas without picking up any Karma, positive or negative.

According to this post, "In sworcery mode left click and hold down on a lagomorph for a few seconds and it should explode"

According to this video guide, you don't need to go anywhere new to find the lagomorphs that you need to kill. The two lagomorphs you indicated are all that need to be found in order to complete this achievement as they can be respawned by leaving and returning to the area. The process is very simple:

1. Kill both lagomorphs.
2. Exit to another screen and return to see the bunnies respawned.
3. Kill both lagomorphs. You will get a message after the first.
4. Exit to another screen and return to see the bunnies respawned.
5. Kill both lagomorphs.
6. Exit to another screen and return to see the bunnies respawned.
7. Kill one more lagomorph. You will get a message.
8. You could try waiting and see if it pops, but in the video guide, although the poster was unsure if it is needed, they exited to the main menu and that's when the achievement appeared for them so it may be necessary to exit to the main menu once the killing is complete.