As the Ontario Environment Ministry continues to study a black sludge flowing out of a storm drain into Fletcher's Creek in Brampton, an environmental group is worried the spill could devastate a rare, endangered species of fish called the Redside dace.

The ministry's Spills Action Centre (SAC) was notified Wednesday morning about the non-oily substance leaking into the creek near Bovaird Drive and McLaughlin Road.

The sludge was first discovered by a team from Lake Ontario Waterkeeper, a charity organization dedicated to cleaning up the province's waterways. The group is trying to expand the habitat for the Redside dace — a type of minnow that gets its name from a wide stripe that extends from its head to its dorsal fin.

The Redside dace is an endangered species of fish that lives in streams flowing out of Lake Ontario and Lake Huron. It can also be found in parts of the U.S. (Government of Ontario) Rebecca Harrison, the manager of programs for the charity, says this spill could be devastating to the fish because it feeds by leaping out of the water and catching insects, and the sludge could obscure its vision.

"It has huge eyes, which tells us that it actually is a visual hunter, so it has to be able to see up through the water to find the bugs that it eats," Harrison said.

She says she knew right away this was not an oil leak.

"To me it almost looked like paint," she said.

Harrison has been working on the project since May but had never actually seen a Redside dace until Tuesday of this week..

"I actually saw one ... jump out of the water right in front of me," she said.

In a statement to the CBC Toronto, a spokesperson for the Environment Ministry said they were able to contain the leak, but it's too early to determine the environmental impact.

They are working with the region and the city of Brampton to assess the damage and identify the source of the spill. ]

Investigators from the ministry collected samples both upstream and downstream from the spill for analysis. They are also keeping staff on the site to assess and oversee the environmental cleanup.

A black substance was found leaking into Fletcher's Creek from this drainage pipe near Bovaird Drive and McLaughlin Road in Brampton. (Lake Ontario Waterkeeper)

The city of Brampton has hired a contractor to try to remove the sludge from the creek using a vacuum truck.

Harrison is hopeful they can get the job done quickly.

"I have not seen a cleanup like this before," she said. "I am very optimistic that it will help, but we'll have to wait and see, honestly."

An investigator holds a jar with a sample of the black substance found in Fletcher's Creek in Brampton. (Lake Ontario Waterkeeper)

Harrison would also like to see whoever is responsible for this spill brought to justice.

"These things happen in streams and rivers all the time and they go completely underreported," she said.

"The people who do that go completely without being fined or found out."