A lizard folk race for a marsh/swamp country

Can you tell me your opinion about this race ? 

Ssillack Lizardfolk

Creature Type. Humanoid
Size. Medium
Speed. 30 feet

Darkvision

You have Darkvision with a range of 60 feet.

Hold Breath

You can hold your breath for up to 15 minutes.

Marsh Adaptation

Difficult Terrain caused by mud, silt, shallow water, or swamp vegetation doesn’t cost you extra movement.

Swim Speed

You have a Swim Speed equal to your Speed.

Keen Senses

You gain proficiency in one of the following skills of your choice: Insight, Perception, or Survival.

Poison Resilience

You have Resistance to Poison damage. You also have Advantage on saving throws you make to avoid or end the Poisoned condition.

Regeneration

You have {{proficiency}} Regeneration Dices (equal to your proficiency). These dice are d6s.

During a Short Rest, you can expend one or more of these dice, roll them, and regain a number of Hit Points equal to the total rolled.

You regain all expended Regeneration Dice when you finish a Long Rest.

Cool.  I might also allow them something similar to the old ranger ability where they can spend one minute camouflaging themselves into natural terrain to gain advantage on Stealth, or something like that. You know, like how Arnold Schwarzenegger hid from the Predator. 

Also, the name Ssillack reminded me of the Sleestak, the lizard creatures from the old 1970s TV show "The Land of the Lost". 

Ty for your answer,
The name was created while i was working on an agglutinative language based on serpent sounds, it's probably what the creators of "the land" of the lost did too. It's the easiest way to create a fantasy language.

I note your idea about stealth, it's a good one.

I was expecting more reactions about the regeneration trait.
As it has almost no combat impact,  i dunno if it's balanced, op, or useless...

But during a short rest, the character can already use their regular hit dice to heal, so the regeneration dice might just be lost in that shadow, especially since most classes have hit dice bigger than d6's. 

Maybe just say they get a +1 hit point to each hit die rolled to heal during a short rest. Or maybe their scaly hide gives them a +1 bonus to their armor class, so they avoid a bit of damage rather than needing to heal so much. Or maybe if they spend their short rest submerged in water or mud, then any hit dice they roll to heal can't roll lower than their Constitution modifier. 

I just like the idea of finding ways to make the game mechanics reinforce the thematic aspect of a character. 

Very fun ideas, i like the wet short rest trick. 

Hi Fulleling!

I am feeling weird being the only with a Profile image.

You are not the only one any longer!

anyhow, the race seems pretty neat, not too OP. Though I do feel like the regeneration may get lost among the other Hit Dice, it's still a neat feature. I think if the campaign isn't in a swamp or coastal area, that the race may lose some functionality however. Though that isn't necessarily a bad thing, and overall I think this is a pretty good race

I used to have a profile image, but then at some point it went away and I don't know why. Thank you for pointing that out so I could fix it.

:-)